มาตรฐานการทดสอบวัสดุงานทาง(กรมทางหลวง)

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

4. °“√√“¬ß“π
§à“°“√¬ÿ∫μ—«¢ÕߧÕπ°√’μ ∑’ˉ¥â„À⮥‡ªìπ√“¬ß“π·≈– √ÿªº≈‡ªìπ‡´π쑇¡μ√ ∑»π‘¬¡ 1

μ”·Àπàß ≈ß„π·∫∫øÕ√塇≈¢∑Ë’ ∫ø. ¡∂.(∑) 103.1-2550 : «‘∏’°“√∑¥ Õ∫§à“°“√¬ÿ∫μ—«¢Õß
§Õπ°√’μ

5. ‡°≥±°å “√μ¥—  π‘ ·≈–§«“¡§≈“¥‡§≈ÕË◊ π∑’ˬա„Àâ
5.1 §“à °“√¬∫ÿ μ—«¢ÕߧÕπ°√’μ„À‡â ªπì ‰ªμ“¡∑°Ë’ ”À𥉫„â πμ“√“ß ¥ß— π’È

™π¥‘ ¢Õßß“π°Õà  √“â ß §“à °“√¬ÿ∫μ—« (´¡.)
 Ÿß ¥ÿ μ“ÌË  ¥ÿ
∞“π√“° 7.5 5
·ºπà æ◊πÈ , §“π, ºπ—ß §. .≈. 10 5
‡ “ 1122.5.5 5
§√∫’ §. .≈. ·≈–ºπ—ß∫“ßÊ 15 5

6. ¢âÕ§«√√–«ß—
6.1 °“√∑¥ Õ∫À“§à“°“√¬∫ÿ μ—«¢ÕߧÕπ°√μ’ ®–‰¡‡à À¡“–°—∫°“√«¥— º≈§“à ¬ÿ∫μ—«¢ÕߧÕπ°√μ’ „π
°√≥’∑Ë«’ — ¥ÿº ¡¡«≈À¬“∫∑Ë„’ ™â¡’¢π“¥‡°π‘ 2 π‘«È ¢÷Èπ‰ª À√Õ◊ °√≥∑’ ’˧Õπ°√μ’ ·Àßâ ‡°‘π‰ª
6.2 „π°“√°√–∑ÿßâ §Õπ°√μ’ ∑¥ Õ∫„π·∫∫πÈ—π §«√°√–∑ÿâß„À∑â «Ë— ∫√‘‡«≥∑’ËÀπ“â μ—¥ ·≈–§«√°√–∑ßÿâ
∫√‘‡«≥¢Õ∫¢Õß·∫∫„Àâ‡∫“°«à“¿“¬„π ‡æË◊ÕªÑÕß°—π¡‘„Àâ·∫∫‡ ’¬À“¬‡πË◊Õß®“°°√–·∑°°—∫
‡À≈Á°°√–∑ÿßâ

7. Àπß—  ◊ÕÕ“â ßÕ‘ß
a. AMERICAN SOCIETY OF TESTING AND MATERIALS ; ASTM STANDARD : C 143-78
b. ¡“μ√∞“πº≈‘μ¿≥— ±åÕÿμ “À°√√¡ ¡Õ°. 213-2520 : §Õπ°√μ’ º ¡‡ √Á®

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡ 1-41

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ. ∫∫øø..¡¡∑∂∂.(.(∑∑))110033.1.1--2255500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
 ∂“π∑’Ë°àÕ √â“ßÇÇÇÇÇÇÇÇÇÇÇÇ.. (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâ∑¥ Õ∫
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ... °“√∑¥ Õ∫§à“°“√¬ÿ∫μ—«¢ÕߧÕπ°√’μ ºŸâμ√«® Õ∫
ºŸâ√—∫®â“ßÀ√◊ÕºŸâπÌ“ àßÇÇÇÇÇÇÇÇÇÇÇ Õπÿ¡μ— ‘
™π‘¥μ—«Õ¬à“ß..ÇÇÇ.Ç.∑¥ Õ∫§√—Èß∑’ËÇÇÇ ((SSLluUmMpP TeEsStT))
∑¥ Õ∫«—π∑’ËÇÇÇÇÇÇÇ.·ºàπ∑’ËÇÇÇÇ

√–¬–§«“¡ Ÿß¢ÕߧÕπ°√’μ∑’Ë∑¥ Õ∫À≈—߬°·∫∫ÕÕ°(H) ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.. ‡´π쑇¡μ√

§“à °“√¬∫ÿ μ«— ¢ÕߧÕπ°√’μ (SLUMP) = 30-H ‡´π쇑 ¡μ√

= ÇÇ.ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ‡´π쇑 ¡μ√

À¡“¬‡Àμÿ :

À¡“¬‡Àμÿ :

1-42 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 103.2-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à °“√¬ÿ∫μ«— ¢ÕߧÕπ°√’μ‚¥¬„™‚â μ–ä °“√‰À≈

(Flow Table)

1. ¢Õ∫¢à“¬
¡“μ√∞“π°“√∑¥ Õ∫πÈ’ §√Õ∫§≈ÿ¡∂ß÷ °“√∑¥ Õ∫À“§“à °“√‰À≈¢ÕߧÕπ°√’μ

2. «‘∏∑’ ”
2.1 ‡§√ËÕ◊ ß¡◊Õ ª√–°Õ∫¥â«¬
2.1.1 ·∫∫ (Mold) ∑”¥«â ¬‚≈À–¡≈’ °— …≥–‡ªπì √Ÿª°√«¬μ—¥ ∞“π¢Õß·∫∫¡’‡ âπºà“π»πŸ ¬°å ≈“ß
254 ¡‘≈≈‘‡¡μ√ (10 πÈ‘«)  à«πμ—¥μÕπ∫π¡’‡ âπºà“π»Ÿπ¬å°≈“ß 171 ¡‘≈≈‘‡¡μ√ (6 3/ π‘È«)

4

¡’§«“¡ Ÿß 127 ¡‘≈≈‘‡¡μ√ (5 πÈ‘«) ª≈“¬∑—Èß Õߢâ“ßμâÕ߇ªî¥ÕÕ°‡ªìπ√–¬–μ—Èß©“°°—∫
·π«»πŸ ¬å°≈“ߢÕß√Ÿª°√«¬ μ—«·∫∫®–μÕâ ß¡’¡Õ◊ ®—∫ Õߢ“â ßÕ¬àŸ∑Ë ’ «à π∫π

5é
1/ é

2

3/8é

10 é
18 Ì

6 3/ é
4

π‘È« 3/8 1/ 5 6 3/
2 4

¡¡. 9.5 12.7 127 171.5

·∫∫ (Mold) °“√∑¥ Õ∫§“à °“√¬∫ÿ μ—«¢ÕߧÕπ°√’μ‚¥¬„™‚â μä–°“√‰À≈

2.1.2 ‚μä–°“√‰À≈ ¡’≈—°…≥–¥—ß√Ÿªμ«— ‚μä–®–μÕâ ߬÷¥μ¥‘ °—∫∞“π§Õπ°√’μ∑Ë¡’ —Ëπ§ß·¢ßÁ ·√ß §◊Õ
 Ÿßª√–¡“≥ 381-508 ¡‘≈≈‘‡¡μ√ (15-20 πÈ‘«) ·≈–¡’πÈ”Àπ—°‰¡àπâÕ¬°«à“ 135 °‘‚≈°√—¡
(300 ªÕπ¥å)

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡ 1-43

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

π«‘È 1/32 1/16 1/14 1/8 1/6 1/4.4 1/4 1/3.2 1/2.56 1/2.1 1/2 1.8 1.6
¡¡. 0.8 1.6 1.9 3.2 3.9 5.9 6.4 7.9 9.9 11.9 12.7 13.9 15.9
π‘«È 1/14 1 1 1/2.3 1 1/8 2 2 1/2.7 3 1/2.5 3 1/2 3 1/1.6 7 1/4 12 17 30
¡¡. 19.1 25.4 36.5 39.7 50.8 60.3 85.7 88.9 92.1 184.2 305 432 76.4

2.1.3 ‡À≈°Á °√–∑ßÿâ (Tamping Rod) ‡ªπì ·∑ßà ‡À≈°Á °≈¡ ¢π“¥‡ πâ ºà“π»Ÿπ¬å°≈“ß 16
¡‘≈≈‡‘ ¡μ√ (5/8 π«È‘ ) ¬“« 610 ¡≈‘ ≈‘‡¡μ√ (24 πÈ«‘ ) ª≈“¬¥â“π∑„Ë’ ™°â √–∑ÿßâ ¡’≈—°…≥–¡π

2.2 ·∫∫øÕ√¡å
„π°“√∫—π∑÷°º≈°“√∑¥ Õ∫ „™â·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 103.2-2550 : «‘∏’°“√∑¥ Õ∫

§à“°“√¬ÿ∫μ—«¢ÕߧÕπ°√μ’ ‚¥¬„™‚â μä–°“√‰À≈
2.3 °“√‡μ√¬’ ¡μ«— Õ¬“à ß

μ—«Õ¬à“߉¥â·°à§Õπ°√’μ´Ë÷ß·∫àß¡“®“°§Õπ°√’μº ¡‡ √Á® ‚¥¬º ¡¡“®“°‚√ßß“πÀ√◊Õ
√∂º ¡§Õπ°√’μ À√◊Õ§Õπ°√’μ®“°‚¡à„πÀπâ“ß“π μâÕß欓¬“¡‡°Á∫®“°À≈“¬ à«π¢Õß‚¡à
·≈«â ®ß÷ π”¡“º ¡„À‡â ªìπ‡πÕÈ◊ ‡¥¬’ «°—π‡æËÕ◊ ∑”°“√∑¥ Õ∫
2.4 °“√∑¥ Õ∫
2.4.1 «“ß·∫∫≈ß°≈“ß‚μä–°“√‰À≈ ‚¥¬„™∞â “π¥“â π°«â“ßÕ¬àŸ¥â“π≈à“ß (‡ πâ ºà“π»Ÿπ¬°å ≈“ß 254

¡‘≈≈‡‘ ¡μ√)

1-44 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ »‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

2.4.2 „ à§Õπ°√’μ∑Ë’®–∑”°“√∑¥ Õ∫≈ß„π·∫∫ª√–¡“≥ 1 „π 2 ¢Õߪ√‘¡“μ√¢Õß·∫∫ „™â
‡À≈°Á °√–∑âÿß °√–∑ßâÿ „Àâ∑Ë«— º‘«¢ÕߧÕπ°√μ’ „π·∫∫ ®”π«π 25 §√—ßÈ

2.4.3 ∑”μ“¡«∏‘ ’ ¢Õâ 2.4.2 Õ°’ §√—Èß „π≈—°…≥–‡¥’¬«°—π „Àâ§Õπ°√’μ‡μÁ¡·∫∫ª“¥º‘«∫π„Àâ
‡√¬’ ∫ ·≈⫬°·∫∫¢πÈ÷ „π·π«¥ßË‘

2.4.4 ª√∫— ‚μä–°“√‰À≈ (Flow Table) ¥«â ¬¡◊ÕÀ¡πÿ „À¬â °¢÷πÈ ≈ß ≈—∫°—π‰ª„π·π«¥Ë‘ß ‚¥¬
¡’√–¬–μà“ߢÕߧ«“¡ Ÿßª√–¡“≥ 12.7 ¡‘≈≈‘‡¡μ√ (1/2 πÈ‘«) 欓¬“¡À¡ÿπ¡◊ÕÀ¡ÿπ ∑’ˬ°
‚μä–∑¥ Õ∫¥â«¬§«“¡‡√Á« ¡Ë”‡ ¡Õ ®”π«π 15 §√—Èß ¿“¬„π√–¬–‡«≈“ª√–¡“≥ 15
«‘π“∑’ «—¥√–¬–∑Ë’§Õπ°√’μ∑¥ Õ∫·ºà°√–®“¬ÕÕ° ‚¥¬§‘¥§à“‡©≈’ˬ®“°√–¬–‡ âπºà“π
»Ÿπ¬°å ≈“ß∑Ë«’ ¥— ‰¥â 6 ∑»‘ ∑“ß

3. °“√§”π«≥
§à“°“√‰À≈¢ÕߧÕπ°√’μ∑Ë’∑¥ Õ∫ ®–°”À𥇪ìπ√âÕ¬≈– ∑’ˇæ‘Ë¡¢÷Èπ¢Õß√–¬–‡ âπºà“π

»πŸ ¬å°≈“ß∑·Ë’ ºÕà Õ°®“°∞“π

§à“√Õâ ¬≈–¢Õß°“√‰À≈ = (D - 25.4) x 100%
25.4

D = √–¬–‡ âπºà“π»πŸ ¬°å ≈“ß∑’Ë·ºÕà Õ° (§“à ‡©≈¬’Ë ) ‡ªìπ‡´π쇑 ¡μ√

4. °“√√“¬ß“π
§à“√âÕ¬≈–¢Õß°“√‰À≈„Àâ„™â∑»π‘¬¡ 1 μ”·Àπàß ∫—π∑÷°„π·∫∫øÕ√å¡ ‡≈¢∑’Ë ∫ø. ¡∂.(∑)

103.2-2550 : «∏‘ ’°“√∑¥ Õ∫§à“°“√¬∫ÿ μ«— ¢ÕߧÕπ°√’μ ‚¥¬„™‚â μ–ä °“√‰À≈

5. ‡°≥±å°“√μ¥—  π‘ ·≈–§«“¡§≈“¥‡§≈ÕË◊ π∑’¬Ë Õ¡„Àâ
5.1 §“à √âÕ¬≈–¢Õß°“√‰À≈ μÕâ ß¡§’ à“Õ¬àŸ√–À«à“ß√Õâ ¬≈– 50 ∂÷ß√Õâ ¬≈– 100

6. ¢âÕ§«√√–«—ß
6.1 °Õà π°“√∑¥ Õ∫μÕâ ߇™Á¥‚μä–∑¥ Õ∫„Àâ –Õ“¥ ª√“»®“°§Õπ°√μ’ ∑’μË °Õ¬àŸπÕ°·∫∫À≈àÕ
6.2 ∑”°“√À¡πÿ ¡◊ÕÀ¡πÿ ‡æ◊ËÕ¬°‚μ–ä °“√‰À≈ „À°â √–∑∫¥â«¬Õ—μ√“§«“¡‡√«Á  ¡”Ë ‡ ¡Õ
6.3 „π¢≥–∑”°“√∑¥ Õ∫¡«≈√«¡®–μÕâ ߉¡à‡°¥‘ °“√·¬°μ«—

7. Àπß—  ◊ÕÕâ“ßÕ‘ß
7.1 AMERICAN SOCIETY OF TESTING AND MATERIALS ; ASTM STANDARD : C 124-71
7.2 §Õπ°√μ’ ‡∑§‚π‚≈¬’ ¢Õß °“√≥ÿ “ „®ªí≠≠“  ∂“∫π— ‡∑§‚π‚≈¬æ’ √–®Õ¡‡°≈â“æ√–π§√‡Àπ◊Õ

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡ 1-45

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√‚ߧ°√“ß√°Ç“√Ç...Ç.....Ç....Ç.....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç..... ∫∫øø.. ¡¡∑∂∂.(.(∑∑)) 110033.2.2--22555500 ∑–‡∫¬’ π
ÇÇ....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç.....Ç....Ç.....Ç....Ç.....Ç..
 ∂“ π∂∑“’Ë°πàÕ∑ Ë°’ √Õà â“ ß√Çâ“ßÇ...Ç....Ç.....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.. (Àπ૬ߓπ∑∑’Ë Ì“°“√∑¥ Õ∫) ∑–‡∫¬’ π∑¥ Õ∫................................
ÇÇ....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç.....Ç....Ç.....Ç....Ç.....Ç.. °“√∑¥ Õ∫§à“°“√¬ÿ∫μ—«¢ÕߧÕπ°√’μ
ºŸâ√—∫º®√⟠â“∫— ß®À“â √ß◊ÕÀº√Ÿâπ◊ÕÌ“º ŸâπàߔǠÇàß...Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç........ ∑¥ Õ∫ÇÇÇÇÇÇ
™π™‘¥πμ—«¥‘ Õμ¬—«à“Õ߬Ǔà ßÇ...Ç.....Ç....∑Ç¥. ∑Õ¥∫ §Õ∫√ßÈ—§∑√.’Ë—Èß..∑...’ËÇ....Ç.....Ç... ‚¥¬„™â‚μä–°“√‰À≈ º∑⟠¥ Õ∫
∑¥∑ Õ¥∫ «Õ—π∫∑«’ËÇπ— ∑Ç.Ë’ ..Ç.....Ç....Ç.....Ç..·Çºàπ.·∑º’Ë..àπ...∑..’ËÇ.....Ç.....Ç....Ç.... (FL(FOloWw TTAabBlLeE) )
ºμ⟠√«® Õ∫

Õπ¡ÿ —μ‘

√–¬–‡ πâ ºà“π»πŸ ¬°å ≈“ß∑Ë·’ ºàÕÕ° (D) ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ. ‡´π쑇¡μ√

√âÕ¬≈–¢Õß°“√‰À≈ = (D › 25.4) x 100%
√Õâ ¬≈–¢Õß°“√‰À≈ 25.4

= ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ

À¡“¬‡Àμÿ :

1-46 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 104-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à πÈ”∑„Ë’ ™â„πß“π§Õπ°√’μ

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫π’È §√Õ∫§≈ÿ¡∂÷ß°“√∑¥ Õ∫§ÿ≥ ¡∫—μ‘∑“ß°“¬¿“æ·≈–∑“߇§¡’¢Õß

πÈ”∑’Ë„™â„π°“√º ¡∑”§Õπ°√’μ·≈–„™â„π°“√∫ࡧÕπ°√’μ ‚¥¬°”Àπ¥§ÿ≥≈—°…≥–∑Ë’μâÕß°“√ «‘∏’
°“√«‘‡§√“–Àå·≈–°“√‡°∫Á μ«— Õ¬“à ß

2. 𑬓¡
2.1 πÈ”∑Ë’„™„â πß“π§Õπ°√μ’ À¡“¬∂ß÷ πÈ”∑Ë’π”¡“„™â„π°“√º ¡‡æ◊ËÕ∑”§Õπ°√μ’ ·≈–/À√◊Õπ”¡“„™â
„π°“√∫ࡧÕπ°√’μ
2.2 Àπ૬ ‡ÕπÁ ∑¬’ Ÿ (NTU, Nephelometric Turbidity Unit) À¡“¬∂÷ß Àπ૬«—¥§“à §«“¡¢ÿπà
„ππ”È
2.3 §“à pH À¡“¬∂ß÷ §“à ∑·Ë’  ¥ß∂÷ߧ«“¡‡ªπì °√¥-¥“à ߢÕßπ”È
2.4 Àπ«à ¬ ppm À¡“¬∂÷ß Àπ÷Ëß à«π„π≈“â π à«π (Parts-Per-Million)

3. «∏‘ ’∑”
3.1 ‡§√Õ◊Ë ß¡◊Õ ·≈–Õÿª°√≥å
3.2 °“√‡°∫Á μ—«Õ¬“à ß ‡æ◊ËÕ„À≥âμ«— ·∑π¢ÕßπÈ”∑μË’ âÕß°“√∑√“∫§ÿ≥≈—°…≥–∑“ß°“¬¿“æ·≈–∑“߇§¡’
°“√‡°Á∫μ—«Õ¬à“ßπÈ”„Àâ∑”°“√‡°Á∫¥â«¬¿“™π–∫√√®ÿ ‚¥¬„™â¢«¥·°â«À√◊Õ¢«¥æ≈“ μ‘° ¡’§«“¡
®ÿ‰¡àπâÕ¬°«à“ 2,500 ≈Ÿ°∫“»°å‡´π쑇¡μ√ ∑Ë’ –Õ“¥·≈–·Àâß °àÕπ∑”°“√‡°Á∫μ—«Õ¬à“ßπÈ”„Àâ„™â
πÈ”∑’Ë®–‡°Á∫≈â“ߢ«¥Õ’°§√È—ßÀπË÷ß Àâ“¡π”¿“™π–∑’ˇ§¬∫√√®ÿ¬“ “√‡§¡’ πÈ”¡—π À√◊Õ Ë‘ßÕ◊Ëπ∑’ˉ¡à
 “¡“√∂≈â“ßÕÕ°‰¥âÀ¡¥¡“„™â„π°“√‡°Á∫μ—«Õ¬à“ßπÈ” «‘∏’°“√‡°Á∫μ—«Õ¬à“ßπÈ”®“°·À≈àßμà“ßÊ
 “¡“√∂°√–∑”‰¥â ¥ß— π’È §◊Õ
3.2.1 πÈ”∫“¥“≈ °Õà π∑”°“√‡°∫Á μ«— Õ¬à“ßπÈ”®“°∫àÕ∫“¥“≈ §«√ ∫Ÿ πÈ”∑ß‘È ª√–¡“≥ 5 π“∑’
·≈â«®÷ß∑”°“√‡°Á∫μ—«Õ¬à“ßπÈ” ∂Ⓡ°Á∫®“°°äÕ°πÈ”¢Õß∫àÕ∫“¥“≈μâÕß≈â“ß°äÕ°„Àâ –Õ“¥
‡ ’¬°àÕπ ·≈â«®÷߇ªî¥πÈ”∑‘È߉«â —° 2-3 π“∑’ ‡æ◊ËÕ„ÀâπÈ”∑’˧â“ßÕ¬Ÿà„π∑àÕ‰À≈ÕÕ°„ÀâÀ¡¥°àÕπ
°“√‡°Á∫μ—«Õ¬à“ßπÈ” ∫√√®ÿ≈ß„π¢«¥§«√‡ªìπ‡«≈“∑Ë’πÈ”‰À≈Õ¬à“ß ¡Ë”‡ ¡Õ √–«—ßÕ¬à“„Àâ
 Ë‘߇®◊ÕªπÕË◊πμ°≈߉ª„π¢«¥ ·≈⫪î¥Ω“®ÿ°„Àâ·πàπ ªî¥©≈“°·®âß√“¬≈–‡Õ’¬¥„π°“√‡°Á∫
§◊Õ  ∂“π∑Ë’‡°Á∫‡«≈“·≈–™Ë◊ÕºŸâ‡°Á∫μ—«Õ¬à“ßπÈ” „Àâ∑”°“√‡°Á∫μ—«Õ¬à“ß Õ¬à“ßπâÕ¬ 2,500
≈°Ÿ ∫“»°‡å ´π쑇¡μ√ ‡æÕË◊ ‡ªπì μ«— ·∑π¢Õß·À≈àßπ”È πÈπ— Ê

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡ 1-47

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

3.2.2 π”È º‘«¥‘π °“√‡°∫Á π”È μ«— Õ¬à“ß®“°Õà“߇°Á∫πÈ” ≈”§≈Õß ·¡πà ”È À√◊Õ·À≈àßπ”È ∏√√¡™“μ‘
ÕË◊πÊ „Àâ∑”°“√‡°Á∫‚¥¬À¬àÕπ¢«¥‡°Á∫πÈ”μ—«Õ¬à“ß ∑’Ë∑”§«“¡ –Õ“¥·≈â«≈߉ª„π·À≈àß
πÈ” ·≈â«√Õ —°§√Ÿà ‡æË◊Õ„Àâ ¿“æπÈ”∑’ˇ°‘¥°“√‡ª≈Ë’¬π·ª≈ß ®“°°“√À¬àÕπ¢«¥‡°Á∫πÈ”
°≈—∫ àŸ ¿“懥‘¡°àÕπ ·≈â«®÷߇ªî¥®ÿ°¢«¥„ÀâπÈ”‰À≈‡¢â“¢«¥ ªî¥®ÿ°„Àâ·πàπ ªî¥©≈“°·®âß
√“¬≈–‡Õ’¬¥„π°“√‡°Á∫ À“°‡ªìπ·À≈àßπÈ”„À≠à „Àâ∑”°“√‡°Á∫μ—«Õ¬à“ßÕ¬à“ßπâÕ¬ 5
μ—«Õ¬à“ß ‡æ◊ËÕ‡ªìπμ—«·∑π ¢Õß·À≈àßπÈ”πÈ—πÊ ·μà≈–®ÿ¥∑’Ë∑”°“√‡°Á∫μ—«Õ¬à“ß„Àâ¡’ª√‘¡“≥
‰¡àμË”°«à“ 1,000 ≈Ÿ°∫“»°å‡´π쑇¡μ√ ‡æË◊Õ∑Ë’®–‰¥â¡’ª√‘¡“≥‡æ’¬ßæÕ∑Ë’„™â„π°“√«‘‡§√“–Àå
‰¥ºâ ≈‡À¡Õ◊ π„π π“¡®√ß‘

3.2.3 πÈ”ª√–ª“ „À∑â ”°“√‡°Á∫μ«— Õ¬“à ßπÈ”ª√–ª“®“°°äÕ° ‚¥¬„™«â ‘∏‡’ ¥’¬«°π— °∫— °“√‡°∫Á πÈ”∫“¥“≈®“°°Õä °
3.3 ·∫∫øÕ√¡å „™â·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 104-2550 : °“√∑¥ Õ∫πÈ”∑„Ë’ ™â„πß“π§Õπ°√μ’
3.4 °“√∑¥ Õ∫

3.4.1 °“√∑¥ Õ∫§ÿ≥ ¡∫—μ‘¢ÕßπÈ”∑“ß°“¬¿“æ ‚¥¬∑”°“√∑¥ Õ∫„π‡√◊ÕË ß§«“¡¢πàÿ ·≈–
§«“¡‡ªìπ°√¥-¥à“ß «‘∏’°“√∑¥ Õ∫∑”μ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 257
: π”È ∫√‚‘ ¿§

3.4.2 °“√∑¥ Õ∫§≥ÿ  ¡∫μ— ‘¢ÕßπÈ”∑“߇§¡’ ∑”°“√«‡‘ §√“–ÀåÀ“ª√‘¡“≥¢Õß´≈— ‡øμ (SO )
4
·≈–§≈Õ‰√¥å (Cl) ¢ÕßπÈ”∑Ë’®–π”¡“„™â„πß“π§Õπ°√’μ ‚¥¬„Àâ∑”μ“¡«‘∏’°“√∑¥ Õ∫
¡“μ√∞“πº≈‘μ¿—≥±åÕμÿ  “À°√√¡ ¡Õ°. 257 : π”È ∫√‘‚¿§

3.4.3 ∑”°“√∑¥ Õ∫‡ª√’¬∫‡∑’¬∫ (Comparative Test) „π‡√ÕË◊ ß°“√∑¥ Õ∫À“√–¬–‡«≈“°“√
°àÕμ—«¢ÕߪŸπ´’‡¡πμå (Setting Time) ·≈–°“√∑¥ Õ∫À“§«“¡μâ“π·√ßÕ—¥
(Compressive Strength) ¢Õß°âÕπ≈Ÿ°∫“»°å¡Õ√åμâ“μ“¡«‘∏’¡“μ√∞“π ¡∂.(∑) 105.1 :
¡“μ√∞“π°“√∑¥ Õ∫§«“¡μâ“π·√ßÕ—¥¢Õß·∑àߧÕπ°√’μ ‚¥¬∑”°“√‡ª√’¬∫‡∑’¬∫
√–À«à“ßπÈ”μ—«Õ¬à“ß∑’Ë®–π”¡“„™â„πß“π§Õπ°√’μ°—∫πÈ”°≈—Ëπ ∑’Ë®–„™âªŸπ´’‡¡πμå„π°“√
∑¥ Õ∫™π¥‘ ‡¥¬’ «°—π

4. °“√√“¬ß“πº≈
„Àâ√“¬ß“πº≈°“√∑¥ Õ∫„π ∫ø. ¡∂.(∑) 104-2550 : °“√∑¥ Õ∫πÈ”∑Ë’„™â„πß“π§Õπ°√’μ

‚¥¬„™â√“¬ß“πº≈°“√∑¥ Õ∫‡√Ë◊Õߧ«“¡¢àÿ𠧫“¡‡ªìπ°√¥-¥à“ß ª√‘¡“≥¢Õß´—≈‡øμ ·≈–§≈Õ-
‰√¥å ”À√—∫√–¬–‡«≈“°“√°àÕμ—«¢ÕߪŸπ´’‡¡πμå ·≈–§«“¡μâ“π·√ßÕ—¥¢Õß°âÕπ≈Ÿ°∫“»°å¡Õ√åμâ“
„À¡â ’√“¬≈–‡Õ¬’ ¥∂ß÷ ∑»π¬‘ ¡ 2 μ”·Àπßà

1-48 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

5. ‡°≥±μå —¥ π‘ ·≈–§«“¡§≈“¥‡§≈ËÕ◊ π∑ˬ’ Õ¡„Àâ

5.1 π”È ∑„Ë’ ™„â πß“π§Õπ°√μ’ ®–μâÕß¡’‡°≥±°å ”Àπ¥§≥ÿ  ¡∫μ— ∑‘ ’ËμâÕß°“√∑“ß°“¬¿“æ ¥ß— π’È §Õ◊ ¡’

§«“¡¢ÿàπ (Turbidity) ‰¡à‡°‘π 2,000 Àπ૬‡ÕÁπ∑’¬Ÿ (NTU) ·≈–®–μâÕß¡’§«“¡‡ªìπ°√¥-¥à“ß

Õ¬àŸ‰¥™â à«ß√–À«“à ß pH 6.5-8.5

5.2 πÈ”∑Ë’„™„â πß“π§Õπ°√’μ ®–μÕâ ß¡‡’ °≥±°å ”Àπ¥§ÿ≥ ¡∫μ— ‘∑“߇§¡’ ∑μË’ âÕß°“√ ¥ß— π’È §◊Õ

μâÕß¡’ª√‘¡“≥´—≈‡øμ„ππÈ”‰¡à‡°π‘ 10,000 ppm.

·≈–®–μâÕß¡’ª√¡‘ “≥¢Õߧ≈Õ‰√¥å„ππ”È ‰¡à‡°π‘ 20,000 ppm.

5.3 °“√∑”°“√∑¥ Õ∫‡ª√¬’ ∫‡∑’¬∫ √–À«“à ßπÈ”μ«— Õ¬à“ß·≈–π”È °≈πË— ®–μÕâ ß„Àºâ ≈°“√∑¥ Õ∫À“

√–¬–°“√°àÕμ—«√–¬–μâπ¢ÕߪŸπ´’‡¡πμå ·μ°μà“ß°—π‰¡à‡°‘π 10 π“∑’ ·≈–º≈°“√∑¥ Õ∫À“°”≈—ß

√∫— ·√ßÕ—¥¢Õß°âÕπ≈Ÿ°∫“»°¡å Õ√μå â“ ®–μÕâ ß„Àâ§à“°”≈ß— √∫— ·√ßÕ—¥μË”≈߉¥â‰¡‡à °π‘ √âÕ¬≈– 10

6. ¢âÕ§«√√–«ß—
6.1 À“°∑”§«“¡ –Õ“¥¢«¥¥â«¬ºß´—°øÕ° ®–μÕâ ß≈â“ß®π·π„à ®‡ ¬’ °Õà π«“à ≈“â ßÕÕ°®πÀ¡¥®√ß‘ Ê
6.2 ‡¡Õ◊Ë ‡°∫Á μ«— Õ¬à“ßπ”È ‡√’¬∫√Õâ ¬·≈«â „À√â ’∫π” àßÀÕâ ߪØ∫‘ μ— °‘ “√ ‡æ◊ÕË ∑”°“√«‘‡§√“–Àå‡√«Á ∑’Ë ÿ¥‡∑“à
∑Ë’®–∑”‰¥â ·≈–‰¡à§«√„À⢫¥πÈ”μ«— Õ¬à“ß∂Ÿ°· ß·¥¥

7. Àπ—ß ◊ÕÕ“â ßÕ‘ß
7.1 THE AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION
OFFICIALS ; AASHTO : T 26-72
7.2 AMERICAN SOCIETY FOR TESTING AND MATERIALS ; ASTM DESIGNATION :
D 1252-60, D 516-63T
7.3 PORTLAND CEMENT ASSOC. (1968) çDESIGN. AND CONTROL OF CONCRETE MIXTUREé
PCA, SKOKI, 1968
7.4 ¡“μ√∞“πº≈μ‘ ¿—≥±Õå μÿ  “À°√√¡ ¡Õ°. 257-2529 : πÈ”∫√‚‘ ¿§

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡ 1-49

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√√Ç...Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç......... ∫∫øø. .¡¡∑∂∂.(.(∑∑)) 110044--22555500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç............ ºŸâ∑¥ Õ∫
  ∂∂““ππ∑∑’Ë°’Ë°àÕÕà   √√â“â“ßßÇ....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç.......... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç............ °“√∑¥ Õ∫π”È ∑’Ë„™â„πß“π§Õπ°√’μ Õπ¡ÿ —μ‘
ººŸâ√â√Ÿ—∫—∫®®â““â ßßÀÀ√√◊ÕÕ◊ ººŸâπâŸπÌ“”  àßßà Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç............ °“√∑¥ Õ∫πÈÌ“∑’Ë„™â„πß“π§Õπ°√’μ
™™ππ‘¥¥‘ μμ—«—«ÕÕ¬¬à““à ßßÇ...Ç....Ç....Ç......Ç......∑∑¥¥  ÕÕ∫∫§§√√È—ß—Èß∑∑Ë’.’ËÇ....Ç....Ç......
∑¥ Õ∫«—π∑.Ë’ .............................·ºàπ∑Ë’.................... 1 μ—«Õ¬à“ß 5
∑¥ Õ∫«—π∑’ËÇÇÇÇÇÇÇ.·ºàπ∑’ËÇÇÇÇ NNTU 2 34

πÈÌ“ÇÇÇÇÇÇÇÇÇÇÇÇÇ pH pH
ª√‘¡“≥πÈÌ“ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ cm3 ppm
·À≈àßπÈÌ“ÇÇÇÇÇÇÇÇ.. ppm

§ÿ≥≈—°…≥– ppppmm

§§««““¡¡¢¢ÿàπÿàπ min min.
NTU

§§««““¡¡‡‡ªªìπìπ°°√√¥¥ ›- ¥¥“àà“ßß

ª√‘¡“≥´—≈‡øμ
ª√¡‘ “≥´—≈‡øμ
ppm.
ª√‘¡“≥§≈Õ‰√¥å
ª√‘¡“≥§≈Õ‰√¥å
ppm.

√–¬–‡«≈“°“√°Õà μ—«¢ÕßªπŸ ´’‡¡πμå

§«“¡μâ“π∑“π·√ßÕ—¥¢Õß°âÕπ≈°Ÿ ∫“»°¡å Õ√åμ“â kg/cm2

À¡“¬‡Àμÿ :

1-50 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 105.1-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à §«“¡μ“â π·√ßÕ—¥¢Õß·∑àߧÕπ°√μ’

(Compressive Strength of Concrete)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫π’È §√Õ∫§≈ÿ¡∂÷ß°“√À“§à“§«“¡μâ“π·√ßÕ—¥¢Õß·∑àߧÕπ°√’μ√Ÿª∑√ß

°√–∫Õ° ·≈–√Ÿª≈°Ÿ ∫“»°å ´Ë÷ß®–‰¥â®“°°“√À≈Õà „π·∫∫À≈Õà À√◊Õ®“°°“√‡®“–¡“∑¥ Õ∫°‰Á ¥â

2. «∏‘ ∑’ ”
2.1 ‡§√ÕË◊ ß¡Õ◊
2.1.1 ‡§√Ë◊Õß°¥∑¥ Õ∫ ‡§√Õ◊Ë ß°¥‡ªπì ·∫∫„¥°Á‰¥â ∑Ë∑’ ”„Àâπ”È Àπ—°°¥‰¥â Ÿß‡æ’¬ßæÕÕ¬àŸ„π™à«ß
„™âß“π‰¥â ·≈–¬Õ¡„À⺑¥æ≈“¥‰¥â‰¡à‡°‘π√âÕ¬≈– 1 ‡§√Ë◊Õß°¥®–μâÕß “¡“√∂‡æË‘¡·√ß°¥
‰¥âÕ¬à“ß ¡Ë”‡ ¡Õ·≈–‰¡à°√–μÿ° ‡§√◊ËÕß∑¥ Õ∫·∫∫À¡ÿπ‡°≈’¬« (Screw-Type) ®–μâÕß
‡ªìπ‡§√◊ËÕß∑Ë’À—«°¥ “¡“√∂‡§≈◊ËÕπ∑Ë’¥â«¬§«“¡‡√Á«ª√–¡“≥ 1.3 ¡‘≈≈‘‡¡μ√μàÕπ“∑’
 ”À√—∫‡§√◊ËÕß∑¥ Õ∫·∫∫‰Œ¥√Õ≈‘° μâÕ߇ªìπ‡§√Ë◊Õß∑Ë’ “¡“√∂„ÀâπÈ”Àπ—°¥â«¬Õ—μ√“
§ß∑’Ë Õ¬„àŸ π™«à ß 1.43 ∂ß÷ 3.47 °‚‘ ≈°√—¡μàÕμ“√“߇´π쇑 ¡μ√μÕà «π‘ “∑’
 à«π∑Ë’„™â°¥¢Õ߇§√◊ËÕß∑¥ Õ∫ ®–μâÕߪ√–°Õ∫¥â«¬·ºàπ‡À≈Á°∑¥ Õ∫ (Steel
Bearing Plate) 2 ·ºàπ ¢π“¥„À≠à°«à“¢π“¥¢Õß·∑àπ∑¥ Õ∫‰¡àπâÕ¬°«à“ 10 ¡‘≈≈‘‡¡μ√
·ºàπ‡À≈Á°μ—«∫π¡’≈—°…≥–‡ªìπ·ªÑπ°¥∞“π§√Ë÷ß∑√ß°≈¡ (Spherically Seated Block)
·¢«π¬÷¥‰«â°—∫‡§√Ë◊Õ߇æË◊Õ„À⢬—∫μ—«‰¥â  à«π·ºàπ‡À≈Á°μ—«≈à“ß ®–μâÕ߬÷¥μ‘¥°—∫ à«π≈à“ß
¢Õ߇§√◊ËÕß ·≈–μâÕß¡’§«“¡Àπ“Õ¬à“ßπâÕ¬ 50 ¡‘≈≈‘‡¡μ√ º‘« —¡º— ¢Õß·ºàπ‡À≈Á°∑—Èß
 Õß ®–μâÕ߇√’¬∫¡’§«“¡‡√’¬∫§≈“¥‡§≈◊ËÕπ‰¥â‰¡à‡°‘π 0.025 ¡‘≈≈‘‡¡μ√ „π√–¬–∑“ß 150
¡‘≈≈‘‡¡μ√ °“√‡æË‘¡·√ß°¥μâÕß∑”‰¥âÕ¬à“ßμàÕ‡πË◊Õß ‰¡à¡’®—ßÀ«–À¬ÿ¥À√◊Õ°√–μÿ°„π
√–À«“à ß°“√‡æ¡‘Ë ·√ß°¥
2.1.2 ‡«Õ√‡å π’¬√§å “≈‘‡ªÕ√å ¡§’ «“¡≈–‡Õ¬’ ¥∂ß÷ 0.1 ¡≈‘ ≈‡‘ ¡μ√
2.1.3 ‡§√Ë◊Õß™Ëß— πÈ”Àπ—° ´Ëß÷ ¡’§«“¡≈–‡Õ’¬¥∂÷ß 1 °√¡—
2.1.4 ‡§√◊ËÕß¡Õ◊ ‡§≈◊Õ∫º«‘ Àπâ“¢Õß·∑ßà §Õπ°√’μ √ªŸ ∑√ß°√–∫Õ°
2.2 ·∫∫øÕ√å¡ „À∫â —π∑÷°„π·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 105.1-2550 : °“√∑¥ Õ∫§«“¡μ“â π·√ßÕ¥—
¢Õß·∑ßà §Õπ°√μ’

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«‘»«°√√¡ 1-51

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

2.3 °“√‡μ√¬’ ¡μ«— Õ¬“à ß
2.3.1 ·∑ßà ∑¥ Õ∫´Ë÷߉¥â®“°°“√À≈àÕ®–μâÕ߇ªìπ√Ÿª∑√ß°√–∫Õ° ¢π“¥‡ πâ º“à π»πŸ ¬å°≈“ß
150+0.75 ¡‘≈≈‘‡¡μ√ ·≈– Ÿß 300+3 ¡‘≈≈‘‡¡μ√ À√◊Õ‡ªìπ√Ÿª≈Ÿ°∫“»°å ¢π“¥ 150+0.75
¡‘≈≈‘‡¡μ√ ‚¥¬∑”°“√‡°Á∫μ—«Õ¬à“ßμ“¡ ¡∂.(∑) 102 : ¡“μ√∞“π°“√‡°Á∫μ—«Õ¬à“ß
§Õπ°√’μ„πÀπâ“ß“π·≈–°“√𔉪∫”√ÿß√—°…“
2.3.2 °“√‡§≈Õ◊ ∫º‘«Àπâ“ (Capping) ·∑àß∑¥ Õ∫√Ÿª∑√ß°√–∫Õ° «— ¥∑ÿ ’Ë„™â„π°“√‡§≈Õ◊ ∫
º‘«Àπâ“√—∫·√ßÕ—¥¢Õß·∑àßμ—«Õ¬à“ß (Capping Compound) μâÕß “¡“√∂√—∫·√ßÕ—¥‰¥â Ÿß
°«à“·√ßÕ—¥¢Õß·∑àߧÕπ°√’μ∑¥ Õ∫ °“√‡§≈◊Õ∫ª≈“¬∑—Èß ÕߢÕß·∑àß∑¥ Õ∫ μâÕß
‡§≈◊Õ∫„ÀâμÈ—ß©“°°—∫·°π¢Õß·∑àß∑¥ Õ∫ §«“¡‡√’¬∫¢Õߺ‘«Àπâ“∑¥ Õ∫∑Ë’‰¥â√—∫°“√
‡§≈◊Õ∫·≈«â ¬Õ¡„À§â ≈“¥‡§≈ÕË◊ π‰¥â‰¡‡à °‘π 0.1 ¡‘≈≈‡‘ ¡μ√
2.3.3 ·∑ßà ∑¥ Õ∫∑’‰Ë ¥®â “°°“√‡®“– ®–μÕâ ߇ªìπ√Ÿª°√–∫Õ°‡ πâ º“à π»πŸ ¬°å ≈“߉¡πà Õâ ¬°«“à 2
‡∑à“ ¢Õß¢π“¥„À≠à∑’Ë ÿ¥¢Õß¡«≈À¬“∫ ·≈–μâÕ߉¡àπâÕ¬°«à“ 100 ¡‘≈≈‘‡¡μ√ §«“¡¬“«
‡¡ÕË◊ ¬—߉¡‡à §≈◊Õ∫ª≈“¬μÕâ ߉¡àπâÕ¬°«“à √Õâ ¬≈– 95 ¢Õ߇ âπºà“π»πŸ ¬å°≈“ß
°àÕπ°“√‡§≈◊Õ∫º‘«·∑àߧÕπ°√’μ∑’ˉ¥â®“°°“√‡®“– ®–μâÕß¡’§«“¡§≈“¥‡§≈◊ËÕπ
¢Õߧ«“¡‡√’¬∫∑Ë’º‘«Àπâ“μ—¥‰¡à‡°‘π 5 ¡‘≈≈‘‡¡μ√ ¢Õß¡ÿ¡∑’ËÀπâ“μ—¥∑”°—∫·°πμ“¡¬“«
®“°¡ÿ¡©“°‰¡à‡°‘π 5 Õß»“ ·≈–‡ âπºà“π»Ÿπ¬å°≈“ß ∑’ËÀπâ“μ—¥∑—Èß Õß®“°‡ âπºà“π
»πŸ ¬°å ≈“߇©≈’¬Ë ‰¡‡à °‘π 2.5 ¡‘≈≈‘‡¡μ√
§«“¡‡√’¬∫¢Õߺ‘«Àπâ“ ·∑àß∑¥ Õ∫∑’ˉ¥â®“°°“√‡®“– ‡¡Ë◊Õ‰¥â√—∫°“√‡§≈◊Õ∫·≈â«
¬Õ¡„Àâ§≈“¥‡§≈Ë◊Õπ‰¥â‰¡à‡°‘π 0.1 ¡‘≈≈‘‡¡μ√ ·∑àß∑¥ Õ∫ ´Ë÷߉¥â®“°°“√‡®“–„À⇮“–‡¡Ë◊Õ
§Õπ°√’μ¡’Õ“¬ÿ‰¡àμË”°«à“ 14 «—π ·≈–μâÕßÕ¬Ÿà„π ¿“æ∑’Ë¥’‰¡à¡’√Õ¬√â“« √Õ¬∫Ë‘πÀ√◊Õ‡ªìπ
‚æ√ß
2.3.4 ∑”°“√«—¥¢π“¥·≈–™ß—Ë πÈ”Àπ°— ·∑ßà ∑¥ Õ∫ ‚¥¬„À«â ¥— À“‡ πâ º“à π»Ÿπ¬°å ≈“ß À√◊Õ¢π“¥
Àπâ“μ—¥·∑àß ’ˇÀ≈Ë’¬¡®—μÿ√— ‡ªìπ‡´π쑇¡μ√ ∑»π‘¬¡ 2 μ”·Àπàß ‚¥¬‡©≈’ˬ§à“‡ âπºà“π
»Ÿπ¬å°≈“ß 2 §à“ ∑’Ë«—¥‰¥âÀ√◊Õ«—¥¢π“¥ Ë’‡À≈’ˬ¡Àπâ“μ—¥∑’˺à“π»Ÿπ¬å°≈“߇©≈Ë’¬ À√◊Õ¢π“¥
∑Ë’«—¥‰¥âπÈ’®–„™â‡ªìπ§à“ ”À√—∫§”π«≥À“æ◊Èπ∑Ë’Àπâ“μ—¥¢Õß·∑àß∑¥ Õ∫ „π°“√«—¥§«“¡ Ÿß
„Àâ«—¥§«“¡ Ÿß¢Õß·∑àß∑¥ Õ∫ √«¡∑ȗߧ«“¡Àπ“¢Õß«— ¥ÿ‡§≈◊Õ∫º‘«Àπâ“Àπ૬‡ªìπ
‡´π쑇¡μ√ ∑»π‘¬¡ 2 μ”·Àπàß °“√™—ËßπÈ”Àπ—°·∑àß∑¥ Õ∫ ‡æ◊ËÕÀ“§«“¡Àπ“·πàπ¢Õß
·∑ßà §Õπ°√’μ „À™â Ëß— π”È Àπ—°·∑àß∑¥ Õ∫‡ªπì °‚‘ ≈°√—¡ ∑»π¬‘ ¡ 2 μ”·Àπàß
2.3.5 °“√«¥— ¢π“¥¢Õß·∑àß∑¥ Õ∫ ´ß÷Ë ‰¥â®“°°“√‡®“– μÕâ ß«¥— „À≥≈â –‡Õ’¬¥∂÷ß 1 ¡‘≈≈‡‘ ¡μ√
¿“¬À≈—ß°“√‡§≈◊Õ∫º‘«Àπâ“¢Õß·∑àß∑¥ Õ∫„Àâ‡√’¬∫°“√«—¥‡ âπºà“π»Ÿπ¬å°≈“ß „Àâ«—¥ 3
μ”·Àπàß §◊Õ ª≈“¬∑—Èß Õߢâ“ß ·≈–∑’Ë°Ë÷ß°≈“ß·∑àß∑¥ Õ∫ ‚¥¬«—¥μ”·Àπàß≈– 2 ·π«
¢Õ߇ âπºà“π»Ÿπ¬å°≈“ß∑Ë’μ—Èß©“°°—∫§à“∑Ë’«—¥‰¥â∑È—ß 6 §à“ π”¡“‡©≈’ˬ‡ªìπ§à“∑’Ë„™â„π°“√

1-52 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ »‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

§”π«≥ °“√«—¥§«“¡¬“« „Àâ«—¥ 4 μ”·Àπàß §◊Õ ∑’˺‘«μ“¡¬“«¢Õß·∑àß∑¥ Õ∫ ‚¥¬¡’
√–¬–Àà“ßμ“¡‡ âπ√Õ∫√Ÿª¢Õß¿“§μ—¥¢«“ß∑Ë’ª≈“¬‡∑à“°—π ·≈â«À“§à“‡©≈Ë’¬ ”À√—∫𔉪
„™„â π°“√§”π«≥
2.4 °“√∑¥ Õ∫
2.4.1 °“√«“ß·∑àß∑¥ Õ∫∫π‡§√Õ◊Ë ß°¥μâÕ߇ªìπ‰ªμ“¡πÈ’
- º«‘ ·ºπà ‡À≈Á°¥â“π ¡— º — °∫— ·∑àß∑¥ Õ∫μâÕß –Õ“¥ª√“»®“°πÈ”¡—π
- ®—¥·π«»πŸ ¬å°≈“ߢÕß·ºπà ‡À≈°Á μÈß— μ«— ∫π·≈–μ—«≈“à ß„ÀâÕ¬àŸ„π·π«‡¥’¬«°—π
- °“√«“ß·∑àß∑¥ Õ∫μâÕß„Àâ·π«·°π¢Õß·∑àß∑¥ Õ∫∑—∫°—∫·π«»Ÿπ¬å°≈“ߢÕ߇§√◊ËÕß
°¥∑¥ Õ∫
- º‘«·ºπà ‡À≈Á°μÕâ ß ¡— º— °∫— ·∑ßà ∑¥ Õ∫·π∫ π‘∑
2.4.2 ‡¡◊ËÕ«“ß·∑ßà ∑¥ Õ∫∫π‡§√Ë◊Õß°¥∑¥ Õ∫ ·≈–®¥— „À·â ºàπ‡À≈°Á  ¡— º — °—∫·∑ßà ∑¥ Õ∫
·π∫ π‘∑¥’·≈â« ®÷߇√Ë‘¡„ÀâπÈ”Àπ—°°¥Õ¬à“ß ¡Ë”‡ ¡Õ ‚¥¬¡’Õ—μ√“§ß∑Ë’Õ¬àŸ„π™à«ß 1.43 ∂÷ß
3.47 °‘‚≈°√—¡μàÕμ“√“߇´π쑇¡μ√μàÕ«‘π“∑’ „π™à«ß§√Ë÷ß·√°¢ÕßπÈ”Àπ—°°¥ Ÿß ÿ¥∑’Ë·∑àß
∑¥ Õ∫®–√—∫‰¥âπ—Èπ ¬Õ¡„Àâ„™âÕ—μ√“°“√°¥ Ÿß°«à“°”Àπ¥‰¥â ·≈–Àâ“¡ª√—∫Õ—μ√“°“√°¥
À√◊Õ à«π„¥Ê ¢Õ߇§√Ë◊Õß∑¥ Õ∫„π¢≥–∑Ë’·∑àß∑¥ Õ∫Õ¬àŸ„π™à«ß®ÿ¥§≈“° (Yield Point)
·≈–®ÿ¥«‘∫—μ‘ (Failure)
2.4.3 „À∑â ”°“√°¥®π°√–∑Ëß— ·∑ßà ∑¥ Õ∫∂÷ß®¥ÿ «‘∫—μ‘ ∫—π∑÷°§“à π”È Àπ—°°¥ Ÿß ÿ¥∑·’Ë ∑àß∑¥ Õ∫
 “¡“√∂√—∫‰¥â ·≈–„Àâ∫—π∑÷°√Ÿª≈—°…≥–°“√·μ°¢Õß·∑àß∑¥ Õ∫π—Èπ„π·∫∫øÕ√å¡ ∑Ë’
∫ø. ¡∂.(∑) 105.1-2550 : °“√∑¥ Õ∫§«“¡μ“â π·√ßÕ—¥¢Õß·∑àߧÕπ°√μ’

3. °“√§”π«≥
3.1 °“√§”π«≥ §à“§«“¡μ“â π·√ßÕ¥— ¢Õß·∑àß∑¥ Õ∫„Àâ≈–‡Õ’¬¥ ∂÷ß∑»π‘¬¡ 2 μ”·Àπßà ‰¥®â “°
 Ÿμ√

§«“¡μ“â π·√ßÕ¥— ¢Õß·∑àß∑¥ Õ∫ = π”È Àπ—°°¥ Ÿß ÿ¥∑’·Ë ∑ßà ∑¥ Õ∫√∫— ‰¥â (°‚‘ ≈°√¡— )
(°‘‚≈°√¡— μÕà μ“√“߇´π쑇¡μ√) æπ◊È ∑ÀË’ πâ“μ—¥∑Ë’√∫— πÈ”Àπ—°°¥¢Õß·∑ßà ∑¥ Õ∫(μ“√“߇´π쇑 ¡μ√)

3.2 °“√§”π«≥À“§à“§«“¡Àπ“·πàπ¢Õß·∑àß∑¥ Õ∫ „Àâ¡’§«“¡≈–‡Õ¬’ ¥∂ß÷ ∑»π‘¬¡ 2 μ”·Àπàß ‰¥â
®“° μŸ √

§«“¡Àπ“·ππà ¢Õß·∑àß∑¥ Õ∫ = π”È Àπ°— ¢Õß·∑ßà ∑¥ Õ∫ (°‚‘ ≈°√—¡)
(°‘‚≈°√—¡μàÕ≈°Ÿ ∫“»°‡å ´π쇑 ¡μ√) ª√‘¡“μ√¢Õß·∑àß∑¥ Õ∫ (≈Ÿ°∫“»°‡å ´π쇑 ¡μ√)

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡ 1-53

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

3.3 ∂â“·∑ßà ∑¥ Õ∫∑‰’Ë ¥®â “°°“√‡®“–¡ ’ à«π ŸßπâÕ¬°«“à 2 ‡∑“à ¢Õ߇ âπºà“π»Ÿπ¬°å ≈“ß„Àâ·°‰â ¢§“à
§«“¡μâ“π·√ßÕ¥— μ“¡ μ“√“ß∑’Ë 1

μ“√“ß∑’Ë 1
Õ—μ√“ à«π§«“¡ ßŸ μÕà ‡ âπºà“π»Ÿπ¬°å ≈“ß°—∫μ—«§≥Ÿ ∑„Ë’ ™·â °‰â ¢§“à §«“¡μâ“π·√ßÕ¥—

Õ—μ√“ à«π§«“¡ ßŸ μ«— μ§—«Ÿ≥§ Ÿ≥Ì“ À”√À∫— √·∫— °·â‰°¢â‰§¢“à §§à“«§“«¡“¥¡“â μπ“â ∑π“·π√·ß√Õߥ— Õ¥—
μàÕ‡ âπºà“π»πŸ ¬å°≈“ߢÕß·∑ßà ∑¥ Õ∫

1.75 0.99

1.50 0.97

1.25 0.94

1.00 0.91

4. °“√√“¬ß“πº≈

„Àâ√“¬ß“πº≈°“√∑¥ Õ∫ ‚¥¬¡’√“¬≈–‡Õ¬’ ¥μ“¡√“¬°“√¥ß— μÕà ‰ªπ’È

- À¡“¬‡≈¢ª√–®”·∑àß∑¥ Õ∫

- ¢π“¥¢Õß·∑àß∑¥ Õ∫

- ·√ßÕ—¥ Ÿß ¥ÿ

- §«“¡μâ“π·√ßÕ—¥

- ≈°— …≥–°“√·μ°

- ¢Õâ ∫°æ√Õà ß ¢Õß·∑ßà ∑¥ Õ∫ À√◊Õ°“√‡§≈◊Õ∫

- ª√–«—μ°‘ “√∫à¡

- «π— ‡¥Õ◊ π ªï ∑∑Ë’ ¥ Õ∫ ·≈–Õ“¬¢ÿ Õß·∑ßà ∑¥ Õ∫ ‡¡ÕË◊ ∑¥ Õ∫

- §«“¡Àπ“·ππà

∫π— ∑÷°º≈μà“ßÊ ‡À≈“à π’È „π·∫∫øÕ√å¡„πÀ—«¢âÕ∑’Ë 2.2

5. ‡°≥±å°“√μ—¥ ‘π ·≈–§«“¡§≈“¥‡§≈Õ◊Ë π∑’¬Ë Õ¡„Àâ
5.1 ‡°≥±„å π°“√æ‘®“√≥“§à“§«“¡μ“â π·√ßÕ—¥¢Õß·∑ßà ∑¥ Õ∫„À⇪πì ‰ªμ“¡ ¡∂. 101 : ¡“μ√∞“π
ß“π§Õπ°√μ’ ·≈–§Õπ°√’μ‡ √‘¡‡À≈°Á
5.2 °“√§”π«≥ §à“§«“¡μ“â π·√ßÕ—¥¢Õß·∑àß∑¥ Õ∫ „Àâ· ¥ß„πÀπ૬°‘‚≈°√¡— μÕà μ“√“ß
‡´π쑇¡μ√ ·≈–¡’§«“¡≈–‡Õ’¬¥∂ß÷ ∑»π‘¬¡ 2 μ”·Àπßà
5.3 °“√§”π«≥ §“à §«“¡Àπ“·πàπ¢Õß·∑àß∑¥ Õ∫ „À·â  ¥ß„πÀπ૬°‘‚≈°√—¡μÕà ≈°Ÿ ∫“»°å
‡´π쇑 ¡μ√ ·≈–¡’§«“¡≈–‡Õ’¬¥∂÷ß ∑»π‘¬¡ 2 μ”·Àπßà
5.4 °“√«¥— ¢π“¥¢Õß·∑ßà ∑¥ Õ∫„À«â —¥„πÀπ«à ¬‡´π쑇¡μ√ ·≈–≈–‡Õ’¬¥∂÷ß∑»π¬‘ ¡ 2 μ”·Àπàß

1-54 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡
5.5  ”À√∫— ·∑àß∑¥ Õ∫√Ÿª∑√ß°√–∫Õ° ∑‰Ë’ ¥®â “°°“√À≈àÕÀ√◊Õ°“√‡®“– ¢π“¥¢Õ߇ πâ º“à π

»Ÿπ¬å°≈“ß ¬Õ¡„Àâ§≈“¥‡§≈◊ËÕπ‰¥â‰¡à‡°‘π √âÕ¬≈– + 0.5 ·≈–§«“¡ Ÿß¬Õ¡„Àâ§≈“¥‡§≈◊ËÕπ‰¥â
‰¡‡à °π‘ √âÕ¬≈– + 1.0
5.6  ”À√∫— ·∑àß∑¥ Õ∫√ªŸ ≈°Ÿ ∫“»°å ¡μ‘ ‘∑ÿ°¥“â π¬Õ¡„À§â ≈“¥‡§≈◊ËÕπ‰¥â‰¡‡à °‘π √Õâ ¬≈– + 0.5

6. ¢âÕ§«√√–«ß—
6.1 „π°√≥∑’ ’∑Ë ¥ Õ∫·∑ßà ∑¥ Õ∫∑’∫Ë à¡™πÈ◊ À“°‡ªìπ·∑ßà ∑¥ Õ∫√ªŸ ≈°Ÿ ∫“»°μå âÕ߇™Á¥º‘«„Àâ·Àßâ
·≈–∑¥ Õ∫¿“¬„π 1 ™—Ë«‚¡ß ·≈–À“°‡ªìπ·∑àß∑¥ Õ∫√Ÿª∑√ß°√–∫Õ°μâÕ߇™Á¥º‘«„Àâ·Àâß
·≈–‡§≈◊Õ∫º‘«Àπ“â ·∑ßà ∑¥ Õ∫∑Èß‘ ‰«â 2 ™—Ë«‚¡ß·≈â«∑¥ Õ∫¿“¬„π 1 ™«Ë— ‚¡ß
6.2  ”À√—∫·∑àß∑¥ Õ∫∑ˉ’ ¥â®“°°“√‡®“– π”¡“·™à„ππÈ”ªŸπ¢“«Õ¡‘Ë μ—«∑Õ’Ë ≥ÿ À¿Ÿ¡À‘ âÕß ‰¡πà Õâ ¬°«“à
24 ™Ë—«‚¡ß ·≈â«®÷߇™Á¥º‘«„Àâ·Àâ߇§≈◊Õ∫º‘«Àπâ“·∑àß∑¥ Õ∫∑‘È߉«â 2 ™Ë—«‚¡ß ·≈â«∑¥ Õ∫
¿“¬„π 1 ™—Ë«‚¡ß
6.3 °“√™Ë—ßπ”È Àπ°— ‡æ◊ËÕÀ“§«“¡Àπ“·ππà ¢Õß·∑àß∑¥ Õ∫ „Àâ™—Ëßπ”È Àπ°— ‡©æ“–·∑àß∑¥ Õ∫‰¡à√«¡
πÈ”Àπ°— ¢Õß« — ¥∑ÿ ‡’Ë §≈◊Õ∫º«‘ Àπâ“
6.4 §«√¡’°“√μ√«® Õ∫‡§√ÕË◊ ß°¥∑„’Ë ™ßâ “πª√–®” ¡”Ë ‡ ¡Õ ªï≈–§√Èß— ·≈–‡¡ÕË◊  ß ¬— «“à ‡§√ËÕ◊ ß
∑¥ Õ∫Õ“®„Àâº≈∑¥ Õ∫‰¡à∂Ÿ°μâÕß À√◊ÕÀ≈—ß®“°°“√´àÕ¡ À√◊Õª√–°Õ∫„À¡à„Àâ∑”°“√
μ√«® Õ∫∑ÿ°§√Èß—

7. ‡Õ° “√Õ“â ßÕß‘
7.1 THE AMERICAN ASSOCIATION OF STATE HIGHWAY OFFICIALS çSTANDARD
SPECIFICATION FOR HIGHWAY MATERIALS AND METHOD OF SAMPLING
AND TESTINGé AASHO T 22-66
7.2 BRITISH STANDARD 1881 : PART 4 : 1974
7.3 ¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 409-2525 : «∏‘ ∑’ ¥ Õ∫§«“¡μ“â π∑“π·√ßÕ—¥¢Õß
·∑àߧÕπ°√’μ

.

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡ 1-55

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ∫∫øø. .¡¡∑∂∂.(.(∑∑))110055.1.1-2-525050 ∑–‡∫’¬π∑¥ Õ∫ ÇÇÇÇÇ..
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ..
 ∂“π∑’Ë°àÕ √â“ßÇÇ.ÇÇÇÇÇÇÇÇÇÇ (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâ∑¥ Õ∫
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.. °“√∑¥ Õ∫§«“¡μâ“π·√ßÕ—¥ ºŸâμ√«® Õ∫
ºŸâ√—∫®â“ßÀ√◊ÕºŸâπÌ“ àß..ÇÇÇÇÇÇÇÇÇÇ Õπÿ¡—μ‘
™π‘¥μ—«Õ¬à“ßÇÇÇ.Ç.∑¥ Õ∫§√—Èß∑’ËÇÇÇ ¢Õß·∑àߧÕπ°√’μ
∑¥ Õ∫«—π∑’Ë..ÇÇÇÇÇÇ.·ºàπ∑’ËÇÇÇÇ
(C(OCMomPRpEreSsSsIVivEe SSTtrReEnNgGthTH
§ÿ≥≈—°…≥– OFofCCOoNnCcRreEtTeE) )

æπÈ◊ ∑Ë’Àπ“â μ—¥∑Ë√’ —∫πÌÈ“Àπ°— °¥¢Õß·∑àß∑¥ Õ∫ (1) ·∑àß∑¥ Õ∫ 4
123

cm.2

πÈÌ“Àπ—°¢Õß·∑ßà ∑¥ Õ∫ (2) kg.
ª√¡‘ “μ√¢Õß·∑àß∑¥ Õ∫ (3) cm.3

πÌÈ“Àπ—°°¥ Ÿß ÿ¥∑Ë’·∑ßà ∑¥ Õ∫√∫— ‰¥â (4) kg.
§«“¡μâ“π·√ßÕ—¥¢Õß·∑ßà ∑¥ Õ∫ = (4)/(1), kg./cm.2
§«“¡Àπ“·πàπ¢Õß·∑ßà ∑¥ Õ∫ = (2)/(3), kg/cm3

À¡“¬‡Àμÿ : ≈—°…≥–°“√·μ°¢Õß·∑àß∑¥ Õ∫

1-56 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 105.2-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§à“°“√√—∫·√ߥ¥— ¢ÕߧÕπ°√’μ

(Flexural Strength of Concrete)

1. ¢Õ∫¢à“¬
¡“μ√∞“π°“√∑¥ Õ∫π’È §√Õ∫§≈ÿ¡∂÷ß°“√∑¥ Õ∫À“§à“°“√√—∫·√ߥ—¥¢ÕߧÕπ°√’μ ‚¥¬

 “¡“√∂∑”‰¥â 2 «‘∏’ §◊Õ «‘∏’„™â·√ß°¥ÀπË÷ß®ÿ¥∑Ë’®ÿ¥°Ë÷ß°≈“ߧ“π (Center-Point Loading) ·≈–«‘∏’
„™â·√ß°¥§“π 2 ®ÿ¥ ‚¥¬„Àâμ”·ÀπàߢÕß®ÿ¥∑—Èß Õ߇ªìπμ”·Àπàß∑Ë’·∫àߧ“πÕÕ°‡ªìπ 3  à«π‡∑à“Ê
°—π (Third-Point Loading)

2. «‘∏∑’ ”
2.1 ‡§√◊ËÕß¡◊Õ
2.1.1 ‡§√ÕË◊ ß°¥∑¥ Õ∫ „™â‡§√◊ËÕß°¥∑ Ë’ “¡“√∂‡æ‘¡Ë ·√ß°¥‰¥Õâ ¬à“ßμàÕ‡πËÕ◊ ß ‰¡¡à ’®—ßÀ«–À¬ÿ¥
À√◊Õ°√–μÿ°„π√–À«à“ß°“√‡æ‘Ë¡·√ß ”À√—∫°“√∑¥ Õ∫°“√√—∫·√ߥ—¥¢ÕߧÕπ°√’μ «‘∏’
„Àâ·√ß°¥Àπ÷Ëß®ÿ¥∑Ë’®ÿ¥°÷Ëß°≈“ߧ“π‰¥â· ¥ß°“√μ‘¥μȗ߇§√◊ËÕß¡◊Õ‰«â„π√Ÿª∑Ë’ 1  à«π «‘∏’„Àâ
·√ß°¥§“π Õß®ÿ¥ ‚¥¬„Àâμ”·ÀπàߢÕß®ÿ¥∑È—ß Õß ‡ªìπμ”·Àπàß∑Ë’·∫àߧ“πÕÕ°‡ªìπ 3
 à«π‡∑“à Ê °π— ‰¥â· ¥ß°“√μ‘¥μ—È߇§√Ë◊Õß¡Õ◊ ‰«â„π√Ÿª∑Ë’ 2
2.1.2 ‡§√◊ËÕß«—¥¢π“¥¢Õߧ“πμ—«Õ¬“à ß ´ßË÷  “¡“√∂«¥— ‰¥≈â –‡Õ¬’ ¥∂ß÷ 0.1 ¡‘≈≈‡‘ ¡μ√
2.2 ·∫∫øÕ√å¡ „™·â ∫∫øÕ√å¡∑’Ë ∫ø. ¡∂.(∑) 105.2-2550 : °“√∑¥ Õ∫°“√√∫— ·√ߥ—¥¢ÕߧÕπ°√’μ
2.3 °“√‡μ√¬’ ¡μ—«Õ¬“à ß
°“√∑¥ Õ∫°“√√—∫·√ߥ—¥¢ÕߧÕπ°√’μ ∑”‰¥â‚¥¬°“√∑¥ Õ∫§“πμ—«Õ¬à“ß¡“μ√∞“π∑Ë’
¡’§«“¡¬“«ª√–¡“≥ 3 ‡∑à“¢Õß à«π Ÿß ‚¥¬∑Ë—«‰ª™‘Èπμ—«Õ¬à“ß®–μâÕß¡’¢π“¥∑’Ë°”Àπ¥„Àâ„π
·μà≈–ß“π §«“¡‡∫Ë’¬ß‡∫π®“°¢π“¥∑’Ë°”Àπ¥®–μâÕ߉¡à‡°‘π 3.2 ¡‘≈≈‘‡¡μ√  ”À√—∫¢π“¥°«â“ß
À√Õ◊ ≈°÷ ‡°‘π 152 ¡≈‘ ≈‡‘ ¡μ√ ¢÷πÈ ‰ª ·≈–‰¡à‡°‘π 1.6 ¡≈‘ ≈‘‡¡μ√  ”À√∫— ¢π“¥‡≈°Á °«“à πÈπ—
2.4 °“√∑¥ Õ∫
2.4.1 «“ß™Èπ‘ ∑¥ Õ∫≈ß∫π∞“π√Õß√—∫§“π «“ßÀ—«°¥„Àμâ ”·ÀπàߢÕßÀ«— °¥ §“π·≈–∞“π√Õß
§“πÕ¬àŸμ“¡°”Àπ¥ ‚¥¬«‘∏’„™â·√ß°¥ÀπË÷ß®ÿ¥∑’Ë®ÿ¥°Ë÷ß°≈“ߧ“π „Àâ®—¥μ”·Àπà߇§√◊ËÕß¡◊Õ
μ“¡°”Àπ¥„π√Ÿª∑Ë’ 1  à«π°“√∑¥ Õ∫«‘∏’„™â·√ß°¥§“π Õß®ÿ¥„Àâ®—¥μ”·Àπà߇§√Ë◊Õß¡◊Õ
μ“¡°”Àπ¥„π √ªŸ ∑Ë’ 2
2.4.2 ª√—∫Õ—μ√“°“√°¥‡§√Ë◊Õß∑¥ Õ∫¥«â ¬·√ߪ√–¡“≥√Õâ ¬≈– 3 ∂÷ß√âÕ¬≈– 6 ¢Õß·√ߪ√–≈—¬
(Ultimate Load) ·≈⫧àÕ¬μ√«® Õ∫º‘« —¡º— ¢Õßμ—«°¥°—∫§“π ·≈–∞“π√Õߧ“π°—∫

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡ 1-57

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡
§“π¥Ÿ«à“¡’™àÕß¢π“¥°«â“ß°«à“ 0.15 ¡‘≈≈‘‡¡μ√ „π™à«ß 25 ¡‘≈≈‘‡¡μ√ À√◊Õ‰¡à ∂â“¡’„Àâ
·μàߧÕπ°√’μ∑Ë’∫√‘‡«≥™à«ßπÈ—πÊ ¥â«¬°“√Ωπ„Àâ‡√’¬∫ ™àÕß∑Ë’¢π“¥°«â“ßπâÕ¬°«à“ 0.15
¡‘≈≈‘‡¡μ√ „π™à«ß 25 ¡‘≈≈‘‡¡μ√ Õ“®Õÿ¥‰¥â‚¥¬°“√«“ß·ºàπÀπ—ß (Leather Shim) ‰«â
√–À«à“ߺ‘« —¡º—  ·ºàπÀπ—ß∑Ë’„™â®–μâÕß¡’¢π“¥‡∑à“°—∫ 6.4 ¡‘≈≈‘‡¡μ√ °«â“ß 25
¡≈‘ ≈‘‡¡μ√ ∂ß÷ 50 ¡‘≈≈‘‡¡μ√

2.4.3 ‡æË¡‘ ·√ß°¥Õ¬à“ßμÕà ‡πËÕ◊ ß ·≈–‰¡à¡°’ “√°√–μÿ°„π™«à ߧ√Ë÷ß·√°¢Õß·√ߪ√–≈¬— Õ“®‡æË‘¡
·√߉¥âÕ¬à“ß√«¥‡√Á« À≈—ß®“°π—Èπ„Àâ‡æ‘Ë¡·√ߥ⫬՗μ√“∑Ë’Õ¬àŸ„π™à«ß 9 °‘‚≈°√—¡μàÕμ“√“ß

1-58 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‡´π쑇¡μ√μàÕπ“∑’ ∂÷ß 12 °‘‚≈°√—¡μàÕμ“√“߇´π쑇¡μ√μàÕπ“∑’ (125 ªÕπ¥åμàÕμ“√“ß
π‘È«μàÕπ“∑’ ∂ß÷ 175 ªÕπ¥åμàÕμ“√“ßπ‘«È μàÕπ“∑)’
2.4.4 «—¥¥â“π°«“â ß·≈–≈°÷ ¢Õߧ“π∑∫Ë’ √‡‘ «≥∑¡’Ë √’ Õ¬·μ°¥“â π≈– 3 §√Èß— ·≈«â À“§“à ‡©≈¬’Ë ¢Õß
Àπâ“μ—¥∑Ë√’ Õ¬·μ° æ√Õâ ¡∑Èß—  ß— ‡°μ≈°— …≥–°“√·μ°√â“«¢Õߧ“πμ—«Õ¬à“ß

3. °“√§”π«≥
°“√§”π«≥§à“°“√√—∫·√ߥ—¥®–°”Àπ¥„ÀâÕ¬Ÿà„π√Ÿª¢Õß ‚¡¥Ÿ≈— ¢Õß°“√·μ°À—° (Modulus

of Rupture) ¥—ßμÕà ‰ªπÈ’
3.1  ”À√∫— °“√°¥ÀπË÷ß®¥ÿ ∑®Ë’ ÿ¥°÷Ëß°≈“ߧ“π (Center-Point Loading)  “¡“√∂À“§“à °“√

√—∫·√ߥ—¥‰¥®â “° μŸ √
R = 3 PI/2bd2

3.2  ”À√—∫°“√°¥ Õß®ÿ¥ ‚¥¬μ”·Àπßà ∑®Ë’ ¥ÿ ∑Èß—  Õß·∫ßà §“πÕÕ°‡ªìπ “¡ «à π (Third-Point
Loading)  “¡“√∂À“§à“°“√√∫— ·√ߥ—¥‰¥â ®“° μŸ √
3.2.1 ‡¡ÕË◊ √Õ¬·μ°Õ¬„àŸ π™«à ß°≈“ߧ“π

R = PI/2bd2

3.2.2 ‡¡Õ◊Ë √Õ¬·μ°Õ¬πŸà Õ°™«à ß°≈“ߧ“π ·≈–À“à ß®“°™«à ß°≈“ß ‰¡‡à °‘π√âÕ¬≈– 5 ¢Õß™à«ß§“π „Àâ„™â

R = 3 PI/2bd2

‡¡Õ◊Ë R = §à“°“√√—∫·√ߥ¥— ‡ªìπ °‚‘ ≈°√—¡μÕà μ“√“߇´π쇑 ¡μ√
P = ·√ß∑Ë®’ ÿ¥«‘∫—μ‘¢Õߧ“𠇪πì °‘‚≈°√—¡
I = ™«à ߧ“𠇪ìπ ‡´π쇑 ¡μ√
b = §«“¡°«â“߇©≈’ˬ∑À’Ë πâ“μ¥— ∫√‘‡«≥√Õ¬·μ° ‡ªπì ‡´π쇑 ¡μ√
d = §«“¡≈÷°‡©≈¬Ë’ ∑Ë’Àπ“â μ¥— ∫√‘‡«≥√Õ¬·μ° ‡ªìπ ‡´π쇑 ¡μ√
a = √–¬–‡©≈ˬ’ ¢Õß√Õ¬·μ°®“°∞“π√Õߧ“π¥“â π„°≈∑â ’Ë ¥ÿ ‡ªìπ ‡´π쑇¡μ√

4. °“√√“¬ß“πº≈
„Àâ√“¬ß“πº≈μ“¡√“¬≈–‡Õ’¬¥„π·∫∫øÕ√å¡∑’Ë ∫ø. ¡∂.(∑) 105.2-2550 : °“√∑¥ Õ∫°“√

√—∫·√ߥ¥— ¢ÕߧÕπ°√’μ

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡ 1-59

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡
5. ‡°≥±°å “√μ¥—  π‘ ·≈–§«“¡§≈“¥‡§≈ÕË◊ π∑¬Ë’ Õ¡„Àâ

5.1 °“√æ‘®“√≥“§“à °“√√∫— ·√ߥ¥— ¢ÕߧÕπ°√μ’ μâÕßÕ¬Ÿ„à π™à«ß √Õâ ¬≈– 11 ∂÷ß√Õâ ¬≈– 23 ¢Õß
§«“¡μ“â π·√ßÕ—¥¢Õß·∑ßà ∑¥ Õ∫´Ëß÷ ‡ªπì §Õπ°√μ’ ∑Ë’º ¡„π§√ßÈ— ‡¥¬’ «°π—

5.2 „π°√≥’¢Õß°“√∑¥ Õ∫«‘∏’„™â·√ß°¥§“π Õß®¥ÿ ∂â“√Õ¬·μ°Õ¬àŸπÕ°™«à ß°≈“ߧ“π·≈–À“à ß
®“°™«à ß°≈“ߧ“π‡°‘π√Õâ ¬≈– 5 ¢Õß™à«ß§“π „À∑â ”°“√∑¥ Õ∫„À¡à

5.3 §“à °“√√∫— ·√ߥ—¥ μâÕߧ”π«≥„Àâ≈–‡Õ’¬¥ ∂ß÷ 0.35 °‘‚≈°√¡— μÕà μ“√“߇´π쇑 ¡μ√ (5 ªÕπ¥å
μÕà μ“√“ßπ‘È«)

6. ¢âÕ§«√√–«ß—
6.1 °“√‡æ¡‘Ë ·√ß°¥®–μÕâ ß°√–∑”Õ¬à“ßμÕà ‡π◊ËÕß ·≈–‰¡¡à ’°“√°√–μ°ÿ
6.2  ”À√—∫μ«— Õ¬à“ß∑∫’Ë à¡™◊πÈ ®–μâÕ߇™¥Á º‘«§“π¡“μ√∞“π∑Ë’®–∑¥ Õ∫„À·â Àßâ ·≈«â ∑¥ Õ∫¿“¬„π
1 ™—Ë«‚¡ß
6.3 §«√¡°’ “√μ√«® Õ∫‡§√ÕË◊ ß°¥∑’Ë„™ßâ “πÕ¬à“ß ¡Ë”‡ ¡Õ À√Õ◊ ‡¡◊ÕË  ß —¬«à“‡§√ÕË◊ ß∑¥ Õ∫Õ“®„Àâ
º≈∑¥ Õ∫‰¡∂à °Ÿ μâÕßÀ√◊ÕÀ≈—ß®“°°“√´Õà ¡ À√Õ◊ ª√–°Õ∫„À¡à„Àâ∑”°“√μ√«® Õ∫∑°ÿ §√—Èß

7. ‡Õ° “√Õâ“ßÕ‘ß
7.1 AMERICAN SOCIETY OF TESTING AND MATERIALS ; ASTM STANDARD : C 78-84, C 293-79

1-60 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√√Ç...Ç....Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç...Ç....... ∫øø.. ¡¡∑∂∂.(.(∑∑))110055..22--2550 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç.......... ºŸâ∑¥ Õ∫
  ∂∂““ππ∑∑’Ë°Ë°’ àÕÕà   √√â““â ßßÇ...Ç....Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç.... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç.... °°““√√∑∑¥¥  ÕÕ∫∫§§««““¡¡μμâ“â“ππ··√√ßߥ¥¥— ¥— Õπÿ¡—μ‘
ºŸâ√√—∫∫— ®®â““â ßßÀÀ√√◊Õ◊ÕººŸâππ⟠̓”  àßßà Ç...Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç....Ç.....
™™ππ‘¥¥‘ μμ—««— ÕÕ¬¬à“à“ßßÇ...Ç....Ç....Ç.....Ç....∑.∑¥¥  ÕÕ∫∫§§√√—ÈßÈ—ß∑∑’ËÇË’..Ç....Ç..... ¢ÕߧÕπ°√’μ
(FL(FElXeUxuRrAaLl SStTreRnEgNtGhTH
∑¥¥  ÕÕ∫∫««—ππ— ∑∑’ËÇ’Ë...Ç....Ç....Ç....Ç....Ç....Ç....·..·ººàπàπ∑∑’ËÇ’Ë..Ç....Ç....Ç......
OoFf COonNcCrRetEeT)E)

°“√°¥Àπ÷Ëß®ÿ¥∑’Ë®ÿ¥°÷Ëß°≈“ߧ“𠧓π∑¥ Õ∫
(CE(CNeTnEteRr--PPOoIiNntTLLoOaAdiDnIgN)G) 1234

·√ß∑’®Ë ÿ¥«‘∫—μ‘¢Õߧ“π (P) kg.

™à«ß§“π (I) cm.

§«“¡°«â“߇©≈’ˬ∑ËÀ’ π“â μ¥— ∫√‡‘ «≥√Õ¬·μ° (b) cm.

§«“¡≈÷°‡©≈’ˬ∑’ËÀπâ“μ—¥∫√‘‡«≥√Õ¬·μ° (d) cm.

§à“°“√√—∫·√ߥ¥— (R) = 3 PI/2bd2 kg./cm.2

°“√°¥ Õß®ÿ¥‚¥¬μÌ“·Àπàß∑’Ë®ÿ¥∑—Èß Õß·∫àߧ“𠧓π∑¥ Õ∫
ÕÕ°‡ªìπ “¡ à«π (THIRD-POINT LOADING) 1234

·√ß∑Ë’®¥ÿ «∫‘ —μ‘¢Õߧ“π (P) kg.

™à«ß§“π (I) cm.

§«“¡°«â“߇©≈’¬Ë ∑’ÀË π“â μ¥— ∫√‡‘ «≥√Õ¬·μ° (b) cm.

§«“¡≈°÷ ‡©≈ˬ’ ∑ËÀ’ πâ“μ¥— ∫√‘‡«≥√Õ¬·μ° (d) cm.

√–¬–‡©≈¬Ë’ ¢Õß√Õ¬·μ°®“°∞“π√Õߧ“π¥â“π„°≈∑â  Ë’ ÿ¥ (a) cm.

§à“°“√√—∫·√ߥ—¥ (√Õ¬·μ°√â“«Õ¬ŸàπÕ°™à«ß°≈“ߧ“π) (R) = 3PI/2bd2 kg./cm.2

§à“°“√√—∫·√ߥ—¥ (√Õ¬·μ°√â“«Õ¬àŸ„π™«à ß°≈“ߧ“π) (R) = PI/2bd2 kg./cm.2

À¡“¬‡Àμÿ :

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ »‘ «°√√¡ 1-61

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 201-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§à“·√ßÕ¥— „π·π«μ—ßÈ ©“°‡ ’Ȭπ¢Õ߉¡â

(Compression Test of Wood Perpendicular to Grain)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫π’È §√Õ∫§≈ÿ¡∂÷ß°“√À“§ÿ≥ ¡∫—μ‘∑“ß°≈¢Õ߉¡â¥â«¬Õ—μ√“·√ßÕ—¥„π

·π«μß—È ©“°‡ ¬’È π ·≈–¥Ÿæƒμ‘°√√¡¢Õ߉¡â ‡¡ËÕ◊ ∂°Ÿ ·√ß°√–∑” ·≈–æ‘®“√≥“À“§“à ∑Ëμ’ âÕß°“√ §◊Õ
1.1 °”≈ß— Õ—¥¢Õ߉¡â ≥ ¢’¥ªØ¿‘ “§ (Elastic Strength at Proportional Limit)
1.2 °”≈ß— Õ¥— ¢Õ߉¡â ≥ ®¥ÿ §≈“° ∑Ë’ 0.05% Offset (Yielding Strength at 0.05% Offset)
1.3 ‚¡¥≈Ÿ — ¬◊¥À¬àÿπ (Modulus of Elasticity)

2. 𑬓¡
§«“¡À¡“¬¢Õߧ”∑Ë’„™â„π¡“μ√∞“π°“√∑¥ Õ∫‰¡âπÈ’ „À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±å

Õÿμ “À°√√¡ ¡Õ°. 421 ‰¡â·ª√√Ÿª : ¢Õâ °”Àπ¥∑—«Ë ‰ª

3. ™È—π§ÿ≥¿“æ·≈– —≠≈—°…≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π

°àÕ √“â ß∑—«Ë ‰ª

4. «∏‘ ’∑”
4.1 ‡§√ËÕ◊ ß¡◊Õ·≈–Õÿª°√≥å ª√–°Õ∫¥«â ¬

‰¡‚§√¡‘‡μÕ√å™π‘¥¡’Àπ⓪í∑¡å (Dial Gauge) ∑Ë’«—¥‰¥â≈–‡Õ’¬¥∂÷ß 0.001 ¡¡. æ√âÕ¡¥â«¬·ºàπ
‡À≈Á°√Õß√—∫ (Dial Micrometer with Bearing Block) ¥—ß· ¥ß„π√ªŸ ∑Ë’ 1

‰¡‚§√¡‡‘ μÕ√å™π¥‘ ¡’Àπ“â ªí¥ ·ºàπ‡À≈Á°°¥
‰¡μâ —«Õ¬“à ß
·ºàπ‡À≈Á°√Õß√—∫

√Ÿª∑’Ë 1 · ¥ß‡§√ËÕ◊ ß¡◊Õ·≈–Õÿª°√≥å °“√∑¥ Õ∫À“§à“·√ßÕ¥— „π·π«μ—Èß©“°‡ ¬È’ π¢Õ߉¡â

1-62 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

4.2 °“√‡μ√¬’ ¡μ—«Õ¬“à ß°“√∑¥ Õ∫
‡μ√’¬¡‰¡âμ—«Õ¬à“ß∑Ë’‰ ‡√’¬∫ (Dressed Timber) ·≈–‡°≈’È¬ß (Clear Wood) ¢π“¥

5x5x15 ´¡. ™π‘¥≈– 3 ∑àÕπ‚¥¬‰¡âμ—«Õ¬à“ß∑’Ë®–π”¡“∑¥ Õ∫μâÕß¡’§à“§«“¡™È◊π (Moisture
Content) Õ¬√Ÿà –À«à“ß√Õâ ¬≈– 10 ∂÷ß √âÕ¬≈– 14
4.3 ·∫∫øÕ√å¡

„™â·∫∫øÕ√å¡∑Ë’ ∫ø. ¡∂.(∑) 201.1-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«μÈ—ß©“°‡ È’¬π
¢Õ߉¡â , 201.2-2550 : °“√∑¥ Õ∫À“§“à ·√ßÕ—¥„π·π«μÈß— ©“°‡ ¬’È π¢Õ߉¡â
4.4 °“√∑¥ Õ∫
4.4.1 ‰¡âμ«— Õ¬à“ß∑∑Ë’ ”°“√∑¥ Õ∫ μâÕß∑”‡ªìπ∑àÕπ ‡Ë’ À≈’ˬ¡¡‡’ πÈÕ◊ ∑’ËÀπ“â μ—¥‡∑“à °—πμ≈Õ¥§«“¡¬“«

·≈–·π«‡ ’¬È π‰¡μâ ßÈ— ©“°°∫— ·°π‰¡â ‚¥¬¡’·ºπà ‡À≈°Á √Õß√∫— ∑“â ¬¢Õ߉¡μâ «— Õ¬à“ß
4.4.2 «¥— ¢π“¥¢Õ߉¡âμ«— Õ¬“à ß ‚¥¬¬Õ¡„Àºâ ‘¥æ≈“¥‰¥â‰¡‡à °‘π 0.2 ¡.¡. ·≈–™ß—Ë π”È Àπ°— Õà“π§à“

≈–‡Õ¬’ ¥‰¥‡â ªπì °√¡— æ√Õâ ¡∑—Èß· ¥ß√Õ¬μ”Àπμ‘ “à ßÊ ¢Õ߉¡∑⠪˒ √“°Ø„Àâ‡ÀÁπ
4.4.3 «“߉¡âμ—«Õ¬à“ß∫π·ºπà ‡À≈°Á √Õß√—∫ (Bearing Block) ‚¥¬„Àâ·π«‡ ’ȬπÕ¬à„Ÿ π·π«

√–¥—∫ ·≈– „À⺑«¥â“πμÈ—ß©“°°—∫«ßªï (Radial) Õ¬ŸàμÕπ∫π ÿ¥ ∫—π∑÷°§«“¡°«â“ߢÕߺ‘«
¥â“ππÈ’ «“ß·ºàπ‡À≈Á°°¥ (Loading Plate) ¢π“¥ 2 π‘È« ´÷Ëß„™â√Õß√—∫πÈ”Àπ—°∑’Ë°¥≈ß
‚¥¬«“ßμ“¡·π«¢«“ß„À≥â°÷Ëß°≈“ß ª√–¡“≥ 1/3  à«π¢Õߧ«“¡¬“«‰¡âμ—«Õ¬à“ß ‚¥¬
„À·â 𫬓«¢Õß·ºàπ‡À≈°Á °¥ ∑”¡¡ÿ ©“°°∫— ·π«¬“«¢Õ߉¡âμ—«Õ¬à“ß
4.4.4 ª√—∫√–¬–§«“¡ ßŸ ¢Õ߉¡‚§√¡‡‘ μÕ√å™π¥‘ ¡’μ—«‡≈¢∫πÀπ“â ªí∑¡å ‚¥¬„Àªâ ≈“¬·°π¢Õß
‰¡‚§√¡‘‡μÕ√å  ¡— º— °—∫º«‘ ¢Õ߉¡μâ «— Õ¬“à ߇≈°Á πÕâ ¬
4.4.5 „ÀâπÈ”Àπ—°°¥≈ߧ√È—ß·√° 100 °‚‘ ≈°√—¡ ·≈–ª√∫— ‡¢Á¡∑À’Ë π⓪í∑¡¢å Õ߉¡‚§√¡‡‘ μÕ√å „Àâ™’È
∑’¢Ë ¥’ »πŸ ¬å
4.4.6 ‡æ¡Ë‘ ·√ß°¥∫π‰¡μâ «— Õ¬à“ßÕ¬à“ßμÕà ‡π◊ËÕߥ⫬§«“¡‡√«Á ª√–¡“≥ 0.5 ¡¡.μàÕπ“∑’ Õ“à π§“à
°“√À¥μ—« (Deformation) ∑Ë’Àπ⓪í∑¡å¢Õ߉¡‚§√¡‘‡μÕ√å ∑ÿ°Ê §√È—ß∑Ë’‡æË‘¡πÈ”Àπ—°°¥
100 °‘‚≈°√—¡ ®π°«à“‡¢Á¡∑Ë’Àπ⓪í∑¡å®–À¡ÿπ‰ª§√∫ 2 √Õ∫ (2 ¡‘≈≈‘‡¡μ√) À√◊Õ‡¢Á¡∑Ë’
Àπ⓪∑í ¡å‡√Ë‘¡À¡πÿ ‰ªÕ¬à“ß√«¥‡√«Á ‚¥¬‰¡Àà ¬ÿ¥
4.4.7 ‡¢’¬π°√“ø ‚¥¬°”Àπ¥„À·â √ß°¥ Õ¬Ÿ∫à π·°πμÈ—ß·≈–°“√À¥μ—«¢Õ߉¡â Õ¬à∫Ÿ π·°ππÕπ
„Àâ· ¥ß§à“°”≈—ßÕ—¥ ≥ ¢’¥ªØ‘¿“§ ·≈–°”≈—ß ≥ ®ÿ¥§≈“° (· ¥ß¥â«¬‡ âπ°√“ø Oû-Aû)
∫π°√“ø¥â«¬ ∂Ⓡ âπ°√“ø‰¡àºà“π®ÿ¥‡√‘Ë¡μâπ„Àâª√—∫·°â„À¡à ‚¥¬„Àâºà“π®ÿ¥‡√‘Ë¡μâπ
(· ¥ß¥«â ¬‡ πâ °√“ø O-A) ¥—ß· ¥ß„π√ªŸ ∑Ë’ 2

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡ 1-63

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

√Ÿª∑’Ë 2 °√“ø· ¥ß§«“¡ —¡æπ— ∏å√–À«à“ß·√ß°¥·≈–°“√À¥μ«— ¢Õ߉¡â
5. °“√§”π«≥

„À⥔‡π‘π°“√§”π«≥μ“¡«‘∏’∑Ë°’ ”À𥉫„â π·∫∫øÕ√¡å μ“¡¢Õâ 4.3

6. °“√√“¬ß“π
„Àâ√“¬ß“πμ“¡·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 201.1-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«μ—Èß

©“°‡ ¬È’ π¢Õ߉¡â , 201.2-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ¥— „π·π«μßÈ— ©“°‡ ¬’È π¢Õ߉¡â

7. ‡°≥±°å “√μ—¥ π‘ ·≈–§«“¡§≈“¥‡§≈◊ÕË π∑’¬Ë Õ¡„Àâ
‡°≥±å°“√μ—¥ ‘π„™â§à“‡©≈Ë’¬°“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«μÈ—ß©“°‡ È’¬π¢Õ߉¡â ·μà≈–™π‘¥

(μ“¡¢âÕ 5, 6 ·≈– 7 „π·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 201.1-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«μÈ—ß
©“°‡ ¬’È π¢Õ߉¡)â

8. ¢âÕ§«√√–«ß—
8.1 §“à ∑’ËÕà“π‰¥®â “°‡§√ÕË◊ ß¡Õ◊ ∑¥ Õ∫ μâÕ߇ªπì §“à ∑’ËÕ“à π‰¥≈â –‡Õ’¬¥ ·≈–∂°Ÿ μâÕß
8.2 ‰¡μâ «— Õ¬“à ß∑Ë®’ –π”¡“∑¥ Õ∫ μÕâ ßÕ¬Ÿà„π ¿“æ∑ ’Ë ¡∫Ÿ√≥å‡√’¬∫√âÕ¬ ¡¢’ π“¥μ“¡∑’Ë°”Àπ¥‡∑à“
°π— μ≈Õ¥∑—ßÈ ∑àÕπ ·≈–μÕâ ߉¡à¡’μ”Àπ„‘ π‡πÕ◊È ‰¡â
8.3 ‰¡âμ—«Õ¬à“ß∑’®Ë –π”¡“∑¥ Õ∫μÕâ ß«“ß„πμ”·Àπßà ∑’Ë∂Ÿ°μÕâ ß ·≈–¡—πË §ßμ“¡·π«∑’°Ë ”Àπ¥
8.4 ·ºàπ‡À≈Á°°¥·≈–·ºπà ‡À≈Á°√Õß√∫— ‰¡âμ—«Õ¬“à ß μâÕßÕ¬„Ÿà πμ”·Àπàß∑ˉ’ ¡à„À⇧≈ËÕ◊ πμ«— ‰¥â
8.5  ∂“π∑Ë’∑¥ Õ∫μâÕ߇ªìπ∑Ë∑’ Ë’‰¡à¡’§«“¡ π—Ë  –‡∑◊Õπ¡“°‡æ√“–®–∑”„Àâ§à“∑Ë’Õà“π®“°‡§√◊ËÕß
∑¥ Õ∫¡§’ «“¡º¥‘ æ≈“¥‰¥âß“à ¬
8.6 °“√‡æË¡‘ ·√ß°¥≈ß∫π‰¡μâ «— Õ¬à“ß À“â ¡‡æ‘¡Ë ·√ß°¥Õ¬“à ß√«¥‡√Á« „À⥔‡π‘π°“√‡æ¡Ë‘ ·√ß°¥∑’≈–
πâÕ¬Õ¬à“ß™â“Ê

1-64 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡
9. Àπß—  Õ◊ Õ“â ßÕ‘ß

9.1 ¡“μ√∞“πº≈‘μ¿≥— ±åÕÿμ “À°√√¡ ¡Õ°. 421-2525 ‰¡·â ª√√ªŸ : ¢âÕ°”Àπ¥∑Ë«— ‰ª
9.2 ¡“μ√∞“πº≈‘μ¿—≥±åÕμÿ  “À°√√¡ ¡Õ°. 424-2530 ‰¡·â ª√√Ÿª :  ”À√∫— ß“π°Õà  √â“ß∑«Ë— ‰ª
9.3 FACULTY OF ENGINEERING CHULALONGKORN UNIVERSITY MATERIAL

TESTING LABORATORY TEST NO.T 3 (COMPRESSION TEST OF WOOD
PERPENDICULAR TO GRAIN)
9.4 ASTM DESIGNATION D 143-83 STANDARD METHODS OF TESTING SMALL
CLEAR SPECIMENS OF TIMBER.
9.5 HARMER E. DAVIS, GEORGE EARL TROXELL AND CLEMENT T. WISKOCIL
THE TESTING AND INSPECTION OF ENGINEERING MATERIALS (THIRD
EDITION)
9.6 FREDERICK F. WANGAARD THE MECHANICAL PROPERTIES OF WOOD.

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡ 1-65

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.. ∫ø.¡∂.(∑) 201.1-2550 ∑–‡∫¬’ π∑¥ Õ∫ÇÇÇÇÇÇ
‚§√ß°“√................................................................ ºŸâ∑¥ Õ∫
 ∂“π∑°Ë’ Õà  √“â ßÇ..ÇÇÇÇÇÇÇÇÇÇÇ. (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
............................................................................... Õπÿ¡—μ‘
Ç Ç∂“Çπ∑Ç°Ë’ ÕàÇ Ç√â“Çß..Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç........ °“√∑¥ Õ∫À“§à“
º.√âŸ..∫—..®...“â ..ß..Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç............ ·√ßÕ—¥„π·π«μ—Èß©“°‡ ’Ȭπ¢Õ߉¡â
ººπ⟠√âŸ“Ì ∫— ®ßà â“Çß.Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç........

™ºπŸâ𥑠”μ «— àßÕ..¬...“à ..ß..Ç....Ç....Ç....Ç........∑..¥... ...Õ..∫...§..√..ßÈ—..∑...ÇË’ ....Ç....Ç..........

∑™¥π ‘¥Õμ∫—««Õπ— ¬∑à“ÇË’ß..Ç....Ç....Ç..∑Ç¥ ÇÕ∫ǧÇ√—Èß·∑º’Ë...πà ...∑..ÇË’....Ç....Ç.........

∑¥ Õ∫«π— ∑.’Ë ..........................·ºπà ∑’Ë.......................

™π‘¥‰¡âμ—«Õ¬à“ß

√“¬≈–‡Õ’¬¥ ‰¡Çâ ÇÇÇÇÇ ‰¡Çâ ÇÇÇÇÇ ‰¡Çâ ÇÇÇÇ.

1 2 3 1 2 3 1 23
¢π“¥¢Õ߉¡â
(´¡.)
æπ◊È ∑Ë’Àπ“È μ¥— μ«— լ˓ß,
1.¡‘μ‘¢Õ߉¡μÈ —«Õ¬“Ë ß A (´¡.2)
§«“¡¬“«¢Õ߉¡â ,
L (´¡.)
2.§«“¡¬“«æ‘°—¥

3.π.π.¢Õ߉¡μâ «— Õ¬“à ß

4.·√ß°¥ ≥ ®ÿ¥§≈“° ∑’Ë 0.05% OFFSET , Py

5.§«“¡‡§âπ¢Õ߉¡â ∑’Ë P.L.
(°(°.°/´./¡´.¡2).2)

S = ·√ß°¥∑’Ë P.L. / æ◊Èπ∑’ËÀπâ“μ—¥¢Õ߉¡â

6.°“Ì ≈ß— Õ¥— ¢Õ߉¡â ≥ ®¥ÿ §≈“°∑Ë’ 0.05
%%OOFFSFSEETT(°(°°./.´/´¡¡.2.)2)

μy = Py / A
7.‚¡¥Ÿ≈— ¬◊¥À¬ÿàπ
(°(°.°/´./¡´.¡2).2)

E = §«“¡‡§âπ ∑’Ë P.L. / §«“¡‡§√’¬¥ ∑’Ë P.L.

À¡“¬‡Àμÿ

1. P.L. À¡“¬∂÷ß PROPORTIONAL LIMIT 4. μy À¡“¬∂÷ß °Ì“≈—ßÕ—¥¢Õ߉¡â ≥ ®ÿ¥§≈“° ∑’Ë 0.05% OFFSET

2. Py À¡“¬∂÷ß ·√ß°¥ ≥ ®ÿ¥§≈“° ∑’Ë 0.05% 5. E À¡“¬∂÷ß ‚¡¥Ÿ≈— ¬◊¥À¬ÿàπ
3. S ÀÀ¡¡“¬“¬∂ß÷∂÷ߧ«“§¡«‡“§¡πâ ‡¢§Õâπߢ‰¡Õâß∑‰¡Ë’ Pâ .∑L’Ë. P.L. 6. e À¡“¬∂÷ß §«“¡‡§√’¬¥ ∑’Ë P.L.

1-66 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

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ºŸâ∑¥ ÕÕ∫∫
‚§√..ß..°...“..√..Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç....Ç.....Ç........ (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ººŸâμ√«® Õ∫∫
°°““√√∑∑¥¥  ÕÕ∫∫ÀÀ““§§à“à“ Õπÿ¡μ— ‘
 ∂ “∂π“∑π°Ë’ ∑Õà Ë°’  àÕ√ “â√ß“â Çß...Ç......Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç......Ç.....
·√ßÕ¥— „π·π«μ—Èß©“°‡ È¬’ π¢Õ߉¡â ‰¡Çâ ÇÇÇÇÇÇ.
ÇÇ....Ç.....Ç....Ç.....Ç....Ç....Ç.....Ç....Ç.....Ç....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç...... §«“¡‡§√’¬¥ (STRAIN)
·√ßÕ—¥„π·π«μ—Èß©“°‡ ’Ȭπ¢Õ߉¡â 123
º√⟠∫—ºâŸ√®—∫“⠮ߓâÇß.Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç....Ç.....Ç....Ç.....Ç....Ç...........
ºπ⟠º“Ì Ÿπâ ”ßà  Çàß.Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç....Ç.....Ç......

™π‘¥μ—«Õ¬“à ß............∑¥ Õ∫§√ßÈ— ∑’Ë.........................

™π¥‘ μ«— Õ¬“à ßÇÇÇÇÇ∑¥ Õ∫§√ßÈ— ∑ÇË’ Ç...Ç

∑¥ Õ∫«π— ∑Ë.’ ..........................·ºπà ∑.’Ë ......................

∑¥ Õ∫«π— ∑ÇË’ ÇÇÇÇÇÇÇ·ºπà ∑ÇË’ ÇÇÇ

™π‘¥‰¡âμ—«Õ¬à“ß

‰¡Çâ ÇÇÇÇÇÇÇÇ ‰¡Çâ ÇÇÇÇÇÇÇ..

·√ß°¥ P (°°.) °“√À¥μ—«¢Õ߉¡â (¡¡.) §«“¡‡§âπ (STRESS)
1 ™àÕß = ÇÇÇÇÇ ¡¡. °°./´¡.2

1 23 123

§à“∑’ËÕà“π‰¥â®“°°√“ø = °°./´¡.2
= °°./´¡.2
1.§§««““¡¡‡§‡§âππâ (E(ELLAASSTTICIC SSTTRREENGTH, S) ¢Õ߉¡∑â Ë’ PP..LL.. =
2. °Ì“≈—ßÕ—¥¢Õ߉¡â ≥ ®ÿ¥§≈“° ∑’Ë 0.05% OFFSET (μy) = °°.
3. ·√ß°¥ ≥ ®ÿ¥§≈“° ∑’Ë 0.05% OFFSET (Py) °°.
4. ·√ß°¥ ∑’Ë P.L.

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡ 1-67

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 202-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§à“·√ßÕ¥— „π·π«¢π“π‡ È¬’ π¢Õ߉¡â

(Compression Test of Wood Parallel to Grain)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫πÈ’ §√Õ∫§≈ÿ¡∂÷ß°“√À“§ÿ≥ ¡∫—μ‘∑“ß°≈¢Õ߉¡â¥â«¬Õ—μ√“·√ßÕ—¥„π

·π«¢π“π‡ ’È¬π ·≈–¥Ÿæƒμ‘°√√¡¢Õ߉¡â ‡¡◊ËÕ∂Ÿ°·√ß°√–∑” μ≈Õ¥®π»÷°…“≈—°…≥–°“√·μ°¢Õß
‰¡â (Failure) ‡¡Õ◊Ë ∂ß÷ ®ÿ¥«‘∫μ— ·‘ ≈â«·≈–æ‘®“√≥“À“§“à ∑Ëμ’ âÕß°“√ §◊Õ
1.1 °”≈—ßÕ¥— ¢Õ߉¡â ≥ ¢¥’ ªØ‘¿“§ (Elastic Strength at Proportional Limit)
1.2 °”≈—ßÕ—¥¢Õ߉¡â ≥ ®ÿ¥§≈“°∑’Ë 0.05% Offset (Yielding Strength At 0.05% Offset)
1.3 °”≈—ßÕ¥— ª√–≈—¬¢Õ߉¡â (Ultimate Strength)
1.4 ‚¡¥≈Ÿ  — ¬¥◊ À¬πàÿ (Modulus of Elasticity)

2. 𑬓¡
§«“¡À¡“¬¢Õߧ”∑Ë’„™â„π¡“μ√∞“π°“√∑¥ Õ∫‰¡âπÈ’ „À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±å

Õÿμ “À°√√¡ ¡Õ°. 421 ‰¡â·ª√√Ÿª : ¢Õâ °”Àπ¥∑Ë«— ‰ª

3. ™Èπ— §≥ÿ ¿“æ·≈– ≠— ≈°— …≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π

°Õà  √“â ß∑—«Ë ‰ª

4. «‘∏∑’ ”
4.1 ‡§√◊ËÕß¡Õ◊ ·≈–Õÿª°√≥å ª√–°Õ∫¥â«¬
4.1.1 ‡§√ÕË◊ ß¡◊Õ∑¥ Õ∫‰¡â
4.1.2 ‡§√◊ËÕß¡Õ◊ «¥— °“√À¥μ—«¢Õ߉¡™â π‘¥∑Ë’¡§’ «“¡¬“«æ°‘ —¥ 15 ´¡. ( Compressometer Having
15 CM. Gauge Length ) ¥—ß· ¥ß„π√Ÿª∑’Ë 1
4.2 °“√‡μ√¬’ ¡μ—«Õ¬“à ß°“√∑¥ Õ∫ ‡μ√’¬¡‰¡μâ «— Õ¬à“ß∑’ˉ ‡√¬’ ∫ (Dressed Timber) ·≈–
‡°≈È’¬ß (Clear Wood) ¢π“¥ 5x5x20 ´¡. ™π‘¥≈– 3 ∑àÕπ ‚¥¬‰¡âμ—«Õ¬à“ß∑Ë’®–π”¡“∑¥ Õ∫
μâÕß¡’§à“§«“¡™È◊π (Moisture Content) Õ¬Ÿà√–À«à“ß√âÕ¬≈– 10 ∂ß÷ √âÕ¬≈– 14
4.3 ·∫∫øÕ√å¡
„™â·∫∫øÕ√å¡∑’Ë ∫ø. ¡∂.(∑) 202.1-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«¢π“π‡ ’È¬π
¢Õ߉¡,â 202.2-2550 : °“√∑¥ Õ∫À“§“à ·√ßÕ¥— „π·π«¢π“π‡ È’¬π¢Õ߉¡â

1-68 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ ‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‰¡‚§√¡‡‘ μÕ√™å 𥑠¡À’ π⓪∑í ¡å ‰¡âμ«— Õ¬“à ß
‡§√◊ÕË ß«¥— °“√À¥μ«— ¢Õ߉¡â™π‘¥∑’Ë¡§’ «“¡¬“«æ‘°¥— 15 ´¡.

√Ÿª∑Ë’ 1 · ¥ß‡§√Õ◊Ë ß¡Õ◊ ·≈–Õÿª°√≥°å “√∑¥ Õ∫À“§“à ·√ßÕ—¥„π·π«¢π“π‡ È¬’ π¢Õ߉¡â

4.4 °“√∑¥ Õ∫
4.4.1 ‰¡μâ —«Õ¬“à ß∑’Ë∑”°“√∑¥ Õ∫ μÕâ ß∑”‡ªìπ∑Õà π Ë’‡À≈ˬ’ ¡¡‡’ πÕÈ◊ ∑ËÀ’ πâ“∑’Ëμ¥— ‡∑“à °—πμ≈Õ¥
§«“¡¬“« ·≈–„π·π«‡ È’¬π‰¡â¢π“π°—∫·°π‰¡â ‚¥¬¡’·ºàπ‡À≈Á°√Õß√—∫∑⓬¢Õ߉¡â
μ—«Õ¬“à ß
4.4.2 «—¥¢π“¥Àπâ“μ—¥‰¡âμ«— Õ¬“à ß‚¥¬¬Õ¡„À⺑¥æ≈“¥‰¥â‰¡à‡°‘π 0.2 ¡.¡.«¥— §«“¡¬“«‚¥¬
¬Õ¡„À⺑¥æ≈“¥‰¥â‰¡à‡°‘π 0.5 ¡.¡.. ·≈–™Ë—ßπÈ”Àπ—°Õà“π§à“≈–‡Õ’¬¥‰¥â‡ªìπ°√—¡ æ√âÕ¡
∑Èß— · ¥ß√Õ¬μ”Àπμ‘ “à ßÊ ¢Õ߉¡â∑ªË’ √“°Ø„Àâ‡ÀπÁ
4.4.3 μ√«® Õ∫‡§√Ë◊Õß¡Õ◊ «¥— °“√À¥μ—«¢Õ߉¡â ∑Ë’«—¥‰¥â≈–‡Õ¬’ ¥∂÷ß 0.001 ¡.¡. ·≈–μ√«®
 Õ∫§«“¡¬“«æ‘°¥— (Gauge Length) ¢Õ߇§√Ë◊Õß¡◊Õ«—¥°“√À¥μ«— ¢Õ߉¡â
4.4.4 μ‘¥μÈß— ‡§√Ë◊Õß¡◊Õ«¥— °“√À¥μ«— ¢Õ߉¡â‡¢â“°∫— ‰¡μâ —«Õ¬“à ß ‚¥¬«“߉¡âμ—«Õ¬à“ß„À‰â ¥â
»Ÿπ¬å°≈“ß °—∫‡§√Ë◊Õß¡◊Õ∑¥ Õ∫ æ√âÕ¡∑—Èߪ√—∫‡§√◊ËÕß¡◊Õ°¥‰¡â ·≈–‡§√Ë◊Õß¡◊Õ«—¥°“√À¥
μ—«¢Õ߉¡â „ÀÕâ “à π∑¢Ë’ ’¥»πŸ ¬å
4.4.5 ‡æ¡Ë‘ ·√ß°¥∫π‰¡μâ —«Õ¬à“ß Õ¬“à ßμàÕ‡πË◊Õߥ⫬§«“¡‡√Á«ª√–¡“≥ 0.6 ¡.¡.μàÕπ“∑’
4.4.6 ∫—π∑°÷ ·√ß∑’°Ë ¥·≈–«¥— °“√À¥μ«— (Deformation) ¢Õ߉¡μâ —«Õ¬à“ß∑ÿ°Ê 500 °°.
¢Õß·√ß∑Ë’°¥ ®π°√–∑—Ë߇°‘π™à«ß¢Õߢ’¥ªØ‘¿“§ À≈—ß®“°π—Èπ„Àâ∂Õ¥‡§√◊ËÕß¡◊Õ«—¥°“√À¥
μ—«¢Õ߉¡âÕÕ° ·≈â«°¥‰¡âμ—«Õ¬à“߉ª®π∂÷ß®ÿ¥«‘∫—μ‘ æ√âÕ¡∑È—ß∫—π∑÷°§à“¢Õß·√ß∑’Ë°¥
 Ÿß ÿ¥
4.4.7 ∫π— ∑°÷ ≈—°…≥–°“√«∫‘ —μ‘ æ√âÕ¡∑ßÈ— ‡¢’¬π¿“æ√Õ¬·μ°¢Õ߉¡âμ—«Õ¬à“ß·μà≈–™‘Èπ ´Ë÷ß
μ—«Õ¬à“ß≈—°…≥–°“√·μ°¢Õ߉¡â ¥ß— · ¥ß„π√ªŸ ∑’Ë 2

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡ 1-69

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

√Õ¬·μ°·∫∫∫¥¬Õà ¬ √Õ¬·μ°√Ÿª≈¡‘Ë √Õ¬·μ°·∫∫·√߇©Õ◊ π
(Crushing) (Wedge Split) (Shearing)

√Õ¬·μ°·∫∫©°’ ª≈“¬ √Õ¬·μ°·∫∫·√ßÕ¥— ·≈–·√߇©Õ◊ π¢π“π‡ ’È¬π √Õ¬·μ°·∫∫·¬°ª≈“¬
(Splitting) (Compression And Shearing Parallel To Grain) (Brooming Or End-Rolling)

√Ÿª∑’Ë 2 · ¥ßμ«— Õ¬à“ß≈—°…≥–°“√«∫‘ —μ‘

4.4.7.1 √Õ¬·μ°·∫∫∫¥¬Õà ¬ ‡°¥‘ ¢÷Èπ‡¡ÕË◊ √Õ¬·μ°Õ¬à„Ÿ π·π«¢π“π‡ ¬’È π
4.4.7.2 √Õ¬·μ°√ªŸ ≈‘Ë¡ ‡°¥‘ ¢÷Èπ‡¡◊ÕË ≈°— …≥–°“√·μ°§≈“â ¬√ªŸ ≈Ë‘¡ ‚¥¬‡ πâ ∑Ë’∂°Ÿ ºà“Õ“®

‡ªπì ‰¥∑â —Èß„π·π«‡ π⠫ߪï À√◊Õ·π«‡ πâ  ¡— º — «ßªï
4.4.7.3 √Õ¬·μ°·∫∫·√߇©Õ◊ π ‡°¥‘ ¢π÷È ‡¡◊ÕË √Õ¬·μ°∑”¡¡ÿ ¡“°°«“à 45 Õß»“ °—∫¥“â π

∫π¢Õ߉¡âμ—«Õ¬à“ß
4.4.7.4 √Õ¬·μ°·∫∫©’°ª≈“¬ ‡°‘¥¢È÷π‡¡ËÕ◊ ‰¡âμ«— Õ¬“à ß¡’μ”Àπ¿‘ “¬„π¡“°Õà π
4.4.7.5 √Õ¬·μ°·∫∫·√ßÕ¥— ·≈–√Õ¬·μ°·∫∫·√߇©◊Õπ¢π“π‡ È’¬π ‡°‘¥¢Èπ÷ ‡¡ËÕ◊ ¡’√Õ¬

·μ°ª√“°Ø„π·π«¢«“߇ ’Ȭπ
4.4.7.6 √Õ¬·μ°·∫∫·¬°ª≈“¬ ‡°‘¥¢÷πÈ ‡πË◊Õß®“°∫√‡‘ «≥ à«πª≈“¬¢Õ߇πÕ◊È ‰¡â¡’

§«“¡™◊πÈ ¡“°‡°‘π‰ª À√Õ◊ ‡°¥‘ ®“°°“√μ¥— ‰¡âμ—«Õ¬à“ß¡“‰¡à¥æ’ Õ
4.4.8 ‡¢¬’ π°√“ø ‚¥¬°”Àπ¥„Àâ·√ß°¥ Õ¬Ÿ∫à π·°πμ—ßÈ ·≈–°“√À¥μ«— ¢Õ߉¡â Õ¬Ÿà∫π·°ππÕπ

„Àâ· ¥ß§à“°”≈—ßÕ—¥ ≥ ¢’¥ªØ‘¿“§ ·≈–°”≈—ß ≥ ®ÿ¥§≈“° (· ¥ß¥â«¬‡ âπ°√“ø Oû-Aû)
∫π°√“ø¥â«¬∂Ⓡ âπ°√“ø‰¡àºà“π®ÿ¥‡√Ë‘¡μâπ„Àâª√—∫·°â„À¡à ‚¥¬„Àâºà“π®ÿ¥‡√Ë‘¡μâπ
(· ¥ß¥â«¬‡ âπ°√“ø O-A) ¥ß— · ¥ß„π√Ÿª∑’Ë 3

1-70 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

√ªŸ ∑Ë’ 3 °√“ø· ¥ß§«“¡ ¡— æ—π∏å√–À«à“ß·√ß°¥·≈–°“√À¥μ—«¢Õ߉¡â
5. °“√§”π«≥

„À⥔‡π‘π°“√§”π«≥μ“¡«∏‘ ∑’ Ë°’ ”À𥉫„â π·∫∫øÕ√å¡ μ“¡¢Õâ 4.3
6. °“√√“¬ß“π

„À√â “¬ß“πμ“¡·∫∫øÕ√¡å „π¢âÕ 4.3
7. ‡°≥±°å “√μ—¥ π‘ ·≈–§«“¡§≈“¥‡§≈Õ◊Ë π∑Ë’¬Õ¡„Àâ

‡°≥±å°“√μ—¥ ‘π„™â§à“‡©≈Ë’¬°“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«¢π“π‡ È’¬π¢Õ߉¡â ·μà≈–™π‘¥
(μ“¡¢âÕ 6,7,8 ·≈– 9 „π·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 202.1-2550 : °“√∑¥ Õ∫À“§à“·√ßÕ—¥„π·π«
¢π“π‡ È¬’ π¢Õ߉¡â)
8. Àπ—ß ◊ÕÕ“â ßÕ‘ß
8.1 ¡“μ√∞“πº≈‘μ¿—≥±åÕμÿ  “À°√√¡ ¡Õ°. 421-2525 ‰¡â·ª√√Ÿª : ¢Õâ °”Àπ¥∑Ë—«‰ª
8.2 ¡“μ√∞“πº≈μ‘ ¿≥— ±Õå ÿμ “À°√√¡ ¡Õ°. 424-2530 ‰¡â·ª√√ªŸ :  ”À√∫— ß“π°Õà  √“â ß∑«—Ë ‰ª
8.3 HARMER E. DAVIS, GEORGE EARL TROXELL AND CLEMENT T. WISKOCIL

THE TESTING AND INSPECTION OF ENGINEERING MATERIALS (THIRD
EDITION)

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡ 1-71

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.. ∫ø.¡¡∑∂..((∑∑)) 220022..11--22555500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇÇ
 ∂“π∑’Ë°àÕ √â“ßÇ.ÇÇÇÇÇÇÇÇÇ.Ç. ºŸâ∑¥ Õ∫
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
ºŸâ√—∫®â“ßÇÇÇÇÇÇÇÇÇÇÇÇ.ÇÇ.. °“√∑¥ Õ∫À“§à“ ºŸâÕπ¡ÿ —μ‘
ºŸâπÌ“ àßÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.
™π‘¥μ—«Õ¬à“ß.ÇÇÇÇ..∑¥ Õ∫§√—Èß∑’ËÇÇ.. ·√ßÕ—¥„π·π«¢π“π‡ ’È¬π¢Õ߉¡â
∑¥ Õ∫«—π∑’ËÇÇÇÇÇÇÇÇ·ºàπ∑’ËÇ..Ç

™π‘¥‰¡âμ—«Õ¬à“ß

√“¬≈–‡Õ’¬¥ ‰¡âÇ..ÇÇÇÇ ‰¡âÇÇÇÇÇÇ ‰¡âÇÇÇÇÇÇ
123
1 231 2 3

æ◊Èπ∑’ÀË πâ“μ—¥μ«— Õ¬à“ß, (´¡.2)
1.¡‘μ‘¢Õ߉¡âμ—«Õ¬à“ß

§«“¡¬“«¢Õ߉¡,â L (´¡.)

2.§«“¡¬“«æ‘°—¥ (´¡.)

3.π.π.¢Õ߉¡âμ—«Õ¬“à ß (°°.)

4.·√ß°¥ ≥ ®ÿ¥§≈“° ∑’Ë 0.05% OFFSET , Py (°°.)

5.·√ß°¥ ≥ ®ÿ¥«∫‘ —μ‘ PMax (°°.)

6.§«“¡‡§âπ¢Õ߉¡â ∑Ë’ P.L. (°°./´¡.2)

S = ·√ß°¥∑Ë’ P.L. / A

7.°Ì“≈—ßÕ¥— ¢Õ߉¡â ≥ ®¥ÿ §≈“°∑Ë’ 0.05% OFFSET
(°°./´¡.2)
8.°Ì“≈—ßÕ—¥ª√–≈—¬¢Õ߉¡â (°°./´¡.2)

CMax = PMax / A (°°./´¡.2)
9.‚¡¥≈Ÿ  — ¬¥◊ À¬àÿπ

E = §«“¡‡§âπ ∑Ë’ P.L. / §«“¡‡§√’¬¥ ∑Ë’ P.L.

À¡“¬‡Àμÿ

11.. PP..LL.. ÀÀ¡¡“¬“∂¬÷ß∂÷ßPPRROOPPOERRTTIOIONNAALLLLIMIMITIT 4. Cy 4. ÀC¡y “¬∂Àß÷¡“°¬”∂≈ß÷ —ß°Õ“Ì —¥≈¢ß— ÕÕ¥— ߢ‰Õ¡ßâ ‰≥¡â ≥®¥ÿ ®§¥ÿ ≈§“≈°“°∑’Ë∑0Ë’ .00.055%%OOFFFFSESTET
2. Py À¡“¬∂÷ß ·√ß°¥ ≥ ®ÿ¥§≈“°∑’Ë 0.05 % OFFSET 5. C À¡“¬∂ß÷ °”≈ß— Õ—¥ª√–≈—¬¢Õ߉¡â

23.. PSy À¡“À¬∂¡ß÷ “·¬√∂ß°ß÷ ¥§≥«“®¡¥ÿ ‡§§≈âπ“¢°∑ÕË’ß0‰.¡05â %∑’Ë PO.FLF.SET max

3. S À¡“¬∂÷ß §«“¡‡§âπ¢Õ߉¡â ∑’Ë P.L. 6. E 5. ÀC¡“M¬ax∂À÷ß¡‚“¡¬¥∂≈Ÿ ÷ß— ¬°◊¥Ì“À≈¬—ßàπÿ Õ—¥ª√–≈—¬¢Õ߉¡â

6. E À¡“¬∂÷ß ‚¡¥Ÿ≈— ¬◊¥À¬ÿàπ

1-72 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇ.ÇÇÇÇÇÇÇÇ. ∫ø.¡∂.(∑) 202.2-2550 ∑–‡∫¬’ π∑¥ Õ∫ÇÇÇÇÇÇÇ
 ∂“π∑°Ë’ Õà  √“â ßÇ.ÇÇÇÇÇÇÇ.ÇÇÇ. ºŸâ∑¥ Õ∫
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ...ÇÇÇ. (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
º√⟠∫— ®“â ßÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.. °“√∑¥ Õ∫À“§à“ Õπÿ¡—μ‘
ºπ⟠“Ì  ßà ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ.
™π¥‘ μ«— Õ¬“à ßÇÇ.ÇÇ∑¥ Õ∫§√ßÈ— ∑ÇË’ Ç.Ç ·√ßÕ—¥„π·π«¢π“π‡ ’È¬π¢Õ߉¡â
∑¥ Õ∫«π— ∑ÇË’ ÇÇÇÇÇ.Ç·ºπà ∑ÇË’ ÇÇ.

·√ß°¥ P (°°.) ‰¡Çâ ÇÇÇÇÇÇÇÇ ™π‘¥‰¡âμ—«Õ¬à“ß ‰¡Çâ ÇÇÇÇÇÇÇ..
°“√À¥μ—«¢Õ߉¡â (¡¡.) ‰¡Çâ ÇÇÇÇÇÇÇÇ §«“¡‡§√’¬¥ (STRAIN)
1 ™àÕß = ÇÇÇÇÇ ¡¡.
1 23 §«“¡‡§πâ (STRESS) °°./´¡.2

1 2 3 1 23

PMax (°°.)
¿“æ√Õ¬·μ°
™π‘¥°“√·μ°

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡ 1-73

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 203-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à §«“¡™◊πÈ ¢Õ߉¡â

(Moisture Content of Wood)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫πȧ’ √Õ∫§≈ÿ¡∂÷ß°“√À“ª√‘¡“≥§«“¡™Èπ◊ ¢Õ߉¡â ‚¥¬«∏‘ Õ’ ∫·Àßâ

2. 𬑠“¡
2.1 §«“¡™Èπ◊ ¢Õ߉¡â À¡“¬∂ß÷ Õ—μ√“ «à π¢ÕßπÈ”Àπ—°¢Õߧ«“¡™◊πÈ ∑Õ’Ë ¬àŸ„π‡π◊ÈÕ‰¡â μÕà πÈ”Àπ°— ¢Õ߉¡∑â Ë’
Õ∫·Àßâ ®ππ”È Àπ°— §ß∑‚’Ë ¥¬§¥‘ ‡ªìπ√âÕ¬≈– (§à“¢Õߧ«“¡™Èπ◊ ¢Õ߉¡âÕ“®¡“°°«“à 100 °‰Á ¥â)
2.2 §«“¡À¡“¬¢Õߧ”∑„Ë’ ™„â π¡“μ√∞“π°“√∑¥ Õ∫‰¡πâ È’ „À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±å
Õμÿ  “À°√√¡ ¡Õ°.421 ‰¡â·ª√√ªŸ : ¢Õâ °”Àπ¥∑«Ë— ‰ª

3. ™—Èπ§ÿ≥¿“æ·≈– —≠≈°— …≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π

°àÕ √â“ß∑Ë—«‰ª

4. «∏‘ ∑’ ”
4.1 ‡§√ËÕ◊ ß¡Õ◊ ·≈–Õÿª°√≥å ª√–°Õ∫¥â«¬
4.1.1 μÕŸâ ∫‰øø“Ñ (Electric Dry Oven) ‡ªìπμŸâÕ∫∑’Ë “¡“√∂ª√∫— ·≈–§«∫§¡ÿ Õÿ≥À¿¡Ÿ ‰‘ ¥â  ”À√∫—
°“√∑¥ Õ∫πÈ’„À⧫∫§ÿ¡∑Ë’Õÿ≥À¿Ÿ¡‘ 103 + 2 Õß»“‡´≈‡´’¬  ‚¥¬μ≈Õ¥„π™à«ß‡«≈“∑Ë’
μâÕß°“√Õ∫‰¡âμ—«Õ¬à“ß ®ππÈ”Àπ—°≈¥≈ߧß∑Ë’ μŸâÕ∫‰øøÑ“§«√¡’Õ“°“»À¡ÿπ‡«’¬π¿“¬„π
‡æ◊ËÕ„ÀÕâ ≥ÿ À¿Ÿ¡‡‘ ∑“à °—π‚¥¬∑«Ë— ·≈–§«√¡™’ àÕß√–∫“¬‰Õπ”È ÕÕ°‰¥¥â ⫬
4.1.2 ‡§√Ë◊Õß™—ßË „À⡧’ «“¡≈–‡Õ’¬¥¢Õß°“√™Ë—ßπ”È Àπ°— ‰¥â ‰¡πà Õâ ¬°«à“ 0.05 °√—¡
4.2 °“√‡μ√’¬¡μ«— Õ¬“à ß
‡μ√’¬¡‰¡âμ—«Õ¬à“ß∑’ˉ ‡√’¬∫ (Dressed Timber) ·≈–‡°≈È’¬ß (Clear Wood) ·≈–μâÕ߉¡à
‡§≈◊Õ∫ “√‡§¡’ ¢π“¥ 2.5x2.5x6 ´¡. ™π¥‘ ≈– 3 ∑Õà π
4.3 ·∫∫øÕ√å¡
„™â·∫∫øÕ√å¡∑’Ë ∫ø. ¡∂.(∑) 203.1-2550 : °“√∑¥ Õ∫À“§à“§«“¡™◊πÈ ¢Õ߉¡â
4.4 °“√∑¥ Õ∫
4.4.1 ¢®—¥‡ ¬’È π‰¡â∑‡Ë’ °“–Õ¬àŸμ“¡º«‘ ¢Õ߉¡âμ«— Õ¬“à ßÕÕ° ·≈–™Ë—ßπ”È Àπ°— ¢Õ߉¡μâ —«Õ¬“à ß ‚¥¬
¬Õ¡„Àâ§≈“¥‡§≈◊ËÕπ‰¥â + 0.05 °√—¡ πÈ”Àπ—°∑’Ë™—Ë߉¥âπ’È®–‡ªìππÈ”Àπ—°¢Õ߉¡âμ—«Õ¬à“ß°àÕπ
Õ∫·Àâß (Original Weight)

1-74 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

4.4.2 π”‰¡âμ«— Õ¬“à ߇¢“â „πμÕ⟠∫ ‚¥¬„À§â «“¡√Õâ πºà“π‰¥∑â «Ë— ∂ß÷ ∑°ÿ ∑Õà π ∑’ËÕÿ≥À¿Ÿ¡‘ 103 + 2
Õß»“‡´≈‡´’¬  μ√«® Õ∫πÈ”Àπ—°¢Õ߉¡âμ—«Õ¬à“ß∑ÿ°Ê ™à«ß√–¬–‡«≈“ 2 ™—Ë«‚¡ß À√◊Õ
®π°«à“‰¡μâ «— Õ¬à“ß®–·Àâß π‘∑ª√“»®“°§«“¡™Èπ◊ ·≈–¡π’ ”È Àπ—°§ß∑’Ë

4.4.3 π”‰¡μâ —«Õ¬“à ßÕÕ°¡“™Ëß— π”È Àπ°— Õ’°§√—ÈßÀπËß÷ ‚¥¬¬Õ¡„À§â ≈“¥‡§≈◊ËÕπ‰¥‰â ¡à‡°π‘ 0.05
°√—¡ πÈ”Àπ—°∑’™Ë ßË— ‰¥âπ’È ®–‡ªìππ”È Àπ°— ¢Õ߉¡âμ—«Õ¬“à ßÀ≈ß— Õ∫·Àâß (Oven Dry-Weight)

5. °“√§”π«≥
„À⥔‡π‘π°“√§”π«≥μ“¡«∏‘ ’∑’Ë°”À𥉫â„π·∫∫øÕ√¡å μ“¡¢Õâ 4.3

6. °“√√“¬ß“π
„À√â “¬ß“πμ“¡·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 203.1-2550 : °“√∑¥ Õ∫À“§“à §«“¡™◊Èπ¢Õ߉¡â

7. ‡°≥±°å “√μ—¥ ‘π·≈–§«“¡§≈“¥‡§≈◊ËÕπ∑’¬Ë Õ¡„Àâ
‡°≥±å°“√μ—¥ ‘π„À⇪ìπ‰ªμ“¡ ¡∂.104 : ¡“μ√∞“πß“π‰¡â „™â§à“‡©≈’ˬ°“√∑¥ Õ∫À“§à“

§«“¡™È◊π¢Õ߉¡â ·μà≈–™π‘¥ (¢âÕ 5 „π·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 203.1-2550 : °“√∑¥ Õ∫À“§à“
§«“¡™π◊È ¢Õ߉¡â )

8. ¢âÕ§«√√–«—ß
8.1 ‰¡âμ«— Õ¬“à ß∑’Ë®–π”¡“∑¥ Õ∫μâÕßÕ¬„àŸ π ¿“æ∑Ë’ ¡∫Ÿ√≥å‡√’¬∫√âÕ¬ ¡¢’ π“¥μ“¡∑°’Ë ”Àπ¥‡∑“à
°—πμ≈Õ¥∑ßÈ— ∑àÕπ ·≈–μâÕ߉¡à¡’ μ”Àπ„‘ π‡π◊ÈÕ‰¡â
8.2 °“√Õ∫‰¡μâ «— Õ¬à“ß À“â ¡Õ∫π“π‡°π‘ §«“¡®”‡ªπì ·≈–Àâ“¡‡°‘π°«“à Õÿ≥À¿Ÿ¡∑‘ ’Ë°”À𥉫â (103 + 2
Õß»“‡´≈‡´’¬ )

9. Àπß—  ◊ÕÕâ“ßÕ‘ß
9.1 ¡“μ√∞“πº≈μ‘ ¿≥— ±åÕÿμ “À°√√¡ ¡Õ°. 421-2525 ‰¡â·ª√√ªŸ : ¢Õâ °”Àπ¥∑—Ë«‰ª
9.2 ¡“μ√∞“πº≈μ‘ ¿≥— ±åÕÿμ “À°√√¡ ¡Õ°. 424-2530 ‰¡·â ª√√Ÿª :  ”À√∫— ß“π°Õà  √â“ß∑«Ë— ‰ª
9.3 FACULTY OF ENGINEERING CHULALONGKORN UNIVERSITY MATERIAL
TESTING LABORATORY TEST NO.T 7 MOISTURE CONTENT OF WOOD,
REVISED : MAY 1983
9.4 ASTM DESIGNATION : D 2016-74 (REAPPROVED 1983) STANDARD TEST
METHODS FOR MOISTURE CONTENT OF WOOD

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡ 1-75

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√√Ç...Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç................. ∫∫øø..¡¡∑∂∂.(.(∑∑)) 203.1--22555500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
  ∂∂““ππ∑∑’Ë°°’Ë àÕÕà   √√â““â ßßÇ...Ç....Ç...Ç....Ç....Ç....Ç....Ç...Ç....Ç.............. ºŸâ∑¥ Õ∫
Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç...Ç....Ç......Ç.............. (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
ººŸâ√â√Ÿ —∫∫— ®®â““â ßßÇ...Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç.............. Õπÿ¡—μ‘
ººŸâπŸâπÌ“”  àßàßÇ....Ç...Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç...Ç....Ç....Ç............... °“°√“√∑∑¥¥  ÕÕ∫∫ÀÀ“§à“§««““¡¡™™◊Èπ◊πÈ ¢¢ÕÕ߉ߡ‰â¡â
™™ππ‘¥¥‘ μμ—««— ÕÕ¬¬à““à ßßÇ...Ç....Ç...Ç..∑.¥.∑ ¥Õ ∫Õ§∫√§ß—È√∑—Èß∑Ë.’ ..’ËÇ...Ç.............
∑∑¥¥  ÕÕ∫∫««—π—π∑∑’ËÇ’Ë...Ç....Ç....Ç....Ç.......Ç.....·...º·àπº∑πà ’Ë..∑ÇË’..................

√“¬≈–‡Õ’¬¥ ‰¡âÇÇÇÇÇÇÇ ™π‘¥‰¡âμ—«Õ¬à“ß ‰¡âÇÇÇÇÇÇ
‰¡âÇÇÇÇÇÇÇ 123
123
123

§«“¡¬“« L. (¡¡.)

1.¡‘μ‘¢Õ߉¡âμ—«Õ¬à“ß §«“¡°«â“ß B. (¡¡.)

§«“¡Àπ“ T. (¡¡.)

2. π.π.¢Õ߉¡μâ —«Õ¬“à ß°àÕπÕ∫·Àßâ W (°√—¡)
(ORIGINAL WEIGHT)

3. π.π.¢Õ߉¡âμ—«Õ¬à“ßÀ≈—ßÕ∫·Àâß WD (°√—¡)
(OVEN DRY WEIGHT)

4. ª√‘¡“≥§«“¡™◊È𠇪ìπ√âÕ¬≈–
M = (WW--WWDD))x/ 1W00D/xW10D0

5. §à“‡©≈’ˬª√‘¡“≥≥§§««““¡¡™™È◊ππ◊È ‡‡ªªìπìπ√√âÕâÕ¬¬≈≈––

À¡“¬‡Àμÿ:

1-76 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 204-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à ·√ߥ—¥¢Õ߉¡â

(Flexture Test of Wood)

1. ¢Õ∫¢à“¬
¡“μ√∞“π°“√∑¥ Õ∫π’È §√Õ∫§≈ÿ¡∂÷ß°“√À“§ÿ≥ ¡∫—μ‘∑“ß°≈¢Õ߉¡â¥â«¬·√ߥ—¥ ·≈–¥Ÿ

æƒμ‘°√√¡¢Õ߉¡â ‡¡Ë◊Õ∂Ÿ°·√ß°√–∑” μ≈Õ¥ ®π≈—°…≥–°“√·μ°¢Õ߉¡â (Failure) ∑Ë’®ÿ¥«‘∫—μ‘
·≈«â ·≈–殑 “√≥“À“§“à ∑’ËμÕâ ß°“√ §Õ◊
1.1 §à“Àπ«à ¬·√ߧ«“¡‡§πâ º‘«πÕ°¢Õ߉¡â ≥ ¢¥’ ªØ¿‘ “§ (Stress in Outer Fiber at Proportional

Limit)
1.2 ‚¡¥Ÿ≈— ·μ°√“â « (Modulus of Rupture)
1.3 ‚¡¥Ÿ≈— ¬◊¥À¬πàÿ (Modulus of ElasticIity)
1.4 §“à Àπ«à ¬·√ߧ«“¡‡§âπ Ÿß ÿ¥¢Õß·√߇©Õ◊ π (Maximum Shearing Stress)
1.5 ‚¡¥Ÿ≈— §◊πμ«— (Modulus of Resilience)
1.6 ≈—°…≥–¢Õß°“√«‘∫μ— ‘ (Type of Failure)

2. 𬑠“¡
2.1 §“à Àπ«à ¬·√ߧ«“¡‡§πâ º«‘ πÕ°¢Õ߉¡â ≥ ¢¥’ ªØ‘¿“§ À¡“¬∂÷ß §“à Àπ૬·√ߧ«“¡‡§πâ ¡“°
∑’Ë ÿ¥∑’Ë°√–∑”∫πº‘«¢Õ߉¡â ·≈–‰¡â “¡“√∂√—∫·√ߧ«“¡‡§âππÈ’‰¥â‚¥¬‰¡à‡°‘¥°“√‡ª≈’ˬπ√Ÿª√à“ß
§ßμ—« (Permanent Deformation)
2.2 ‚¡¥≈Ÿ  — ¬◊¥À¬ÿπà À¡“¬∂ß÷ §à“§ÿ≥ ¡∫μ— ∑‘ “ß°≈∑Ë’„™«â —¥æ‘°¥— §«“¡·¢Áß·°√ßà (Stiffness) ¢Õß
‰¡â‡¡◊ËÕ¡’·√ߧ«“¡‡§âπ°√–∑”∑Ë’‰¡πâ È—π
2.3 ‚¡¥Ÿ≈ — ·μ°√“â « À¡“¬∂ß÷ æ‘°—¥¢Õߧà“Àπ૬·√ߥ—¥∑‡’Ë ≈¬¢Õ∫‡¢μ¢Õß ¡¡ÿμ‘∞“π „π°“√
æ ‘ ®Ÿ πå Ÿμ√·√ߥ—¥
2.4 ‚¡¥≈Ÿ — §π◊ μ—« À¡“¬∂÷ß §à“§≥ÿ  ¡∫μ— ‘∑“ß°≈∑„’Ë ™«â —¥æ‘°¥— §«“¡‡Àπ¬’ « (Toughness) À√Õ◊
æ‘°—¥¢Õß§à“¢’¥§«“¡ “¡“√∂μàÕ°“√μâ“π·√ß°√–·∑° (Shock-Resistance) ¢Õ߉¡â ‡¡Ë◊Õ¡’·√ß
§«“¡‡§πâ °√–∑”∑ˉ’ ¡âππ—È
2.5 §“à Àπ૬·√ߧ«“¡‡§âπ Ÿß ¥ÿ ¢Õß·√߇©Õ◊ π À¡“¬∂÷ß §à“§«“¡ “¡“√∂¢Õ߉¡∑â Ë’∑πμàÕ·√ß
§«“¡‡§âπ Ÿß ÿ¥ ‚¥¬∑”„Àâ‡πÈ◊Õ‰¡â à«πÀπ÷Ë߇§≈Ë◊Õπμ—«À√◊Õ·¬°À≈ÿ¥ÕÕ°®“°‡π◊ÈÕ‰¡âÕ’° à«π
Àπ÷ßË ∑’ËÕ¬àŸμ¥‘ °—π

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡ 1-77

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

2.6 πÈ”Àπ°— ª√–≈¬— (Ultimate Load) À¡“¬∂ß÷ πÈ”Àπ—° ßŸ  ¥ÿ ¢Õߧ“à ·√ߧ«“¡‡§πâ ∑’Ë°√–∑”
∫π‰¡â ≥ ®¥ÿ «‘∫μ— ‘

3. ™—Èπ§ÿ≥¿“æ·≈– —≠≈—°…≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π

°àÕ √“â ß∑—Ë«‰ª

4. «‘∏’∑”
4.1 ‡§√ËÕ◊ ß¡Õ◊ ·≈–Õÿª°√≥å ª√–°Õ∫¥â«¬
4.1.1 ‡§√ÕË◊ ß∑¥ Õ∫‰¡â (Wood Testing Machine)
4.1.2 ‡§√Õ◊Ë ß¡◊Õ«—¥°“√·Õàπμ«— ¢Õ߉¡â
4.2 °“√‡μ√’¬¡μ«— Õ¬à“ß
‡μ√’¬¡‰¡âμ—«Õ¬à“߉ ‡√’¬∫ (Dressed Timber) ·≈–‡°≈È’¬ß (Clear Wood) ¢π“¥ 5x5x90
´¡.™π‘¥≈– 3 ∑àÕπ‚¥¬‰¡âμ—«Õ¬à“ß∑Ë’®–π”¡“∑¥ Õ∫μâÕß¡’§à“§«“¡™◊Èπ (Moisture Content)
Õ¬Ÿà√–À«à“ß√âÕ¬≈– 10 ∂÷ß √âÕ¬≈– 14
4.3 ·∫∫øÕ√å¡
„™â·∫∫øÕ√å¡∑Ë’ ∫ø. ¡∂.(∑) 204.1-2550 : °“√∑¥ Õ∫À“§à“·√ߥ—¥¢Õ߉¡â ∂÷ß 204.4-
2550 : °“√∑¥ Õ∫À“§à“·√ߥ—¥¢Õ߉¡â
4.4 °“√∑¥ Õ∫
4.4.1 «¥— ¢π“¥·≈–™—ËßπÈ”Àπ—°¢Õ߉¡μâ —«Õ¬à“ß·μà≈–∑Õà π ‡¢’¬π¿“æ “¡¡‘μ¢‘ Õ߉¡âμ—«Õ¬à“߉«â
æ√âÕ¡∑—Èß· ¥ß√Õ¬μ”Àπ‘ ∑‘»∑“ß·≈–®”π«π«ßªï∑’ËÀπâ“μ—¥¢Õ߉¡âμ—«Õ¬à“ß ∑ÿ°Ê √–¬–
2.50 ´¡. ‡æ◊ÕË ‡ªìπ¢âÕ¡Ÿ≈°“√æ‘®“√≥“À≈—ß°“√∑¥ Õ∫
4.4.2 ®—¥μ”·ÀπàߢÕߪ≈“¬∞“π√Õß√∫— „Àâ¡√’ –¬–Àà“ß 70 ´¡. «“߉¡μâ —«Õ¬à“ß„πμ”·Àπßà ∑ºË’ ‘«
 —¡º— °—∫‡ âπ«ßªï (Tangertial Surface) À√◊Õº‘«μ“¡·π«‡ È’¬π∑Ë’Õ¬Ÿà„°≈≠≡â (Pith)
∑’Ë ÿ¥ ‚¥¬Àß“¬Àπâ“¢È÷π‡æË◊Õ„À⇧√Ë◊Õß∑¥ Õ∫°¥πÈ”Àπ—°≈ß¡“ À√◊Õ«“߉¡âμ—«Õ¬à“ß„À⺑«
μ“¡·π«‡ È’¬π„°≈≠≡â∑Ë’ ÿ¥ ‚¥¬§«Ë”Àπâ“≈߇¡◊ËÕ„™â‡§√Ë◊Õß∑¥ Õ∫¥÷߉¡âμ—«Õ¬à“ߢ÷Èπ
·≈–¬÷¥πÈ”Àπ—°∑Ë°’ ¥‰¡‰â «âÕ¬“à ß¡—Ëπ§ßμ“¡√ªŸ ∑Ë’ 1

1-78 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

π”È Àπ°— °¥

L/2 = 35 ´¡. L/2 = 35 ´¡.

L = 70 ´¡.

√Ÿª∑Ë’ 1 · ¥ß°“√∑¥ Õ∫À“§à“·√ߥ¥— ¢Õ߉¡â

4.4.3 ‡§√◊ËÕß¡Õ◊ «—¥°“√·Õπà μ—«¢Õ߉¡â ·≈–‡§√Õ◊Ë ß∑¥ Õ∫‰¡â∑’Ë®–∑”°“√∑¥ Õ∫„ÀâÕà“π§à“∑Ë’¢¥’ »Ÿπ¬å
4.4.4 °¥π”È Àπ°— μÕà ‡πÕ◊Ë ßÕ¬“à ß™“â Ê ¥«â ¬§«“¡‡√«Á 2.5 ¡¡. μÕà π“∑’ Õ“à π§“à °“√·Õπà μ«— ∑’Ë

°÷Ëß°≈“ߢÕ߉¡âμ—«Õ¬à“ß ·≈–πÈ”Àπ—°°¥·μà≈–§√È—ß∑Ë’‡æ‘Ë¡¢÷Èπ‡ªìπ™à«ß‡∑à“Ê °—π ´Ë÷ßÕ¬à“ß
πâÕ¬∑’Ë ÿ¥®–μâÕßÕà“π‰¥â 20 §à“ °àÕπ∂÷ß®ÿ¥ª√–≈—¬ (Ultimate) ·≈–„Àâ∫—π∑÷°§à“¢ÕßπÈ”
Àπ—°ª√–≈¬— ‰«¥â ⫬
4.4.5 ∫—π∑÷°≈°— …≥–¢Õß°“√«∫‘ μ— ‘∑Ë’ª√“°Ø∫π‰¡μâ —«Õ¬“à ß À≈ß— ®“°∑°Ë’ ¥π”È Àπ—°®π∂÷ß®¥ÿ
ª√–≈—¬·≈«â
4.4.6 ‡¢¬’ π°√“ø· ¥ß§«“¡ ¡— æ—π∏å √–À«à“ßπÈ”Àπ—°°¥∑’ˇæË‘¡¢÷πÈ ·≈–§“à °“√·Õπà μ—« ‚¥¬„Àâ
Õ¬„Ÿà π·°πμ—ßÈ ·≈–·°ππÕπμ“¡≈”¥∫—
4.4.7 §”π«≥À“§à“μà“ßÊ ∑Ëμ’ Õâ ß°“√¥ß— · ¥ß‰«„â π·∫∫øÕ√å¡ ∫ø. ¡∂.(∑) 204.2-2550
: °“√∑¥ Õ∫À“§à“·√ߥ¥— ¢Õ߉¡â

√Õ¬·μ°‡π◊ÕË ß®“°·√ߥ÷ß (Simple Tension) √Õ¬·μ°·∫∫‡ª√“–¢“¥ (Brash Tension)
(¿“楓â π¢â“ß) (¿“楓â π≈à“ß)

√Õ¬·μ°¢«“߇ ’¬È π (Cross-Grain Tension) √Õ¬·μ°‡πËÕ◊ ß®“°·√ß°¥ (Compression)
(¿“æ¥â“π¢“â ß) (¿“æ¥â“π¢â“ß)

√Õ¬·μ°·∫∫øπí ª≈“ (Splintering Tension) √Õ¬·μ°·∫∫©’°μ“¡·π«πÕπ (Horizontal Shear)
(¿“楓â π≈à“ß) (¿“楓â π¢â“ß)

√ªŸ ∑Ë’ 2 · ¥ßμ—«Õ¬à“ß≈—°…≥–¢Õß°“√«‘∫—μ‘

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡ 1-79

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡
5. °“√§”π«≥

„À⥔‡π‘π°“√§”π«≥μ“¡«‘∏’∑’°Ë ”À𥉫„â π·∫∫øÕ√å¡ ¢âÕ 4.3
6. °“√√“¬ß“π

„Àâ√“¬ß“πμ“¡·∫∫øÕ√å¡ „π¢âÕ 4.3
7. ‡°≥±°å “√μ—¥ ‘π·≈–§«“¡§≈“¥‡§≈ÕË◊ π∑¬Ë’ Õ¡„Àâ

‡°≥±å°“√μ—¥ ‘π„À⇪ìπ‰ªμ“¡ ¡∂. 104 : ¡“μ√∞“πß“π‰¡â ‚¥¬„™â§à“‡©≈’ˬ°“√∑¥ Õ∫
À“§“à ·√ߥ¥— ¢Õ߉¡â ·μà≈–™π‘¥
8. Àπ—ß ◊ÕÕ“â ßÕ‘ß
8.1 ¡“μ√∞“π «. .∑. ¡“μ√∞“π ”À√∫— Õ“§“√‰¡â æ‘¡æå§√È—ß∑Ë’ 5 情¿“§¡ 2526
8.2 ¡“μ√∞“πº≈‘μ¿≥— ±åÕμÿ  “À°√√¡ ¡Õ°. 424-2530 ‰¡â·ª√√Ÿª :  ”À√∫— ß“π°àÕ √“â ß∑—Ë«‰ª
8.3 FACULTY OF ENGINEERING,CHULALONGKORN UNIVERSITY MATERIAL

TESTING LABORATORY,: TEST NO.T1 çFLEXURE TEST OF WOOD,é REVISED :
MAY 1983
8.4 HARMER E. DAVIS, GEORGE EARL TROXELL AND CLEMENT T. WISKOCIL
THE TESTING AND INSPECTION OF ENGINEERING MATERIALS : THIRD
EDITION
8.5 FREDERICK F. WANGAARD THE MECHANICAL PROPERTIES OF WOOD

1-80 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√.......................................................... ∫∫∫øøø..¡.¡∑∂∂.(.(∑∑))2220044.1.1--2255555000 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
‚ §∂√“ßπ°“∑√’Ë°ÇàÕ Ç√“â Çß.Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç........ ºŸâ∑¥ Õ∫
 ..∂..“..π...∑..’Ë°...àÕ.. ...√..â“..ß..Ç....Ç....Ç....Ç.....Ç....Ç......Ç....Ç....Ç....Ç......... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
Ǻ√ŸâÇ—∫Ç®“â Çß...Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç......Ç......... Õπ¡ÿ μ— ‘
ººŸâ√Ÿâπ—∫”® â“àßß.Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç......Ç....Ç....Ç....Ç........ °°““√√∑∑¥¥  ÕÕ∫∫ÀÀ““§§à“à“··√√ßߥ¥—¥¥— ¢¢ÕÕß߉¡‰¡â â

º™ŸâππÌ“¥‘  μàß«—ÇÕ¬Çà“ßÇ...Ç....Ç....Ç.∑¥Ç ÇÕ∫ǧ√ÇÈ—ß∑ÇË.’ ..Ç....Ç.............
™∑𥑥 μÕ—«∫Õ«¬—πà“∑ß’Ë.Ç....Ç....Ç......Ç......∑...¥... ..Õ·∫º§πà √∑—Èß.Ë’ .∑...’ËÇ....Ç........

∑¥ Õ∫«—π∑’ËÇÇÇÇ..ÇÇÇ·ºàπ∑’ËÇÇ..

™π‘¥‰¡âμ—«Õ¬à“ß

·√ß°¥ P (°°.) ‰¡âÇÇÇÇÇÇÇÇ ‰¡âÇÇÇÇÇÇ.. ‰¡âÇÇÇÇÇÇÇÇ
°“√·Õàπμ—«¢Õ߉¡â Δ °“√·Õàπμ«— ¢Õ߉¡â Δ °“√·Õπà μ«— ¢Õ߉¡â Δ
(¡.¡.) (¡.¡.) (¡.¡.)

1 ™àÕß = ÇÇÇÇÇ ¡.¡. 1 ™Õà ß = ÇÇÇÇÇ ¡.¡. 1 ™àÕß = ÇÇÇÇÇ ¡.¡.

123123123

·√ß°¥ Ÿß ÿ¥
Pmax (°°.)

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ ‘»«°√√¡ 1-81

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√Ç√..Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç...Ç......Ç....Ç...Ç............... ∫∫ø.¡∑∂∂.(.∑(∑))220044.2-255500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇ
 ∂“π∑’Ë°Õà  √“â ß...............................................
 ∂“π∑’Ë°àÕ √â“ßÇÇÇÇÇÇÇÇ..ÇÇ. (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºâŸ∑¥ Õ∫
Ç...Ç....Ç....Ç...Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç...Ç....Ç......Ç...Ç............ ºâŸμ√«® Õ∫
ººŸâ√√Ÿâ —∫—∫®®â““âßßÇ..Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç...Ç....Ç......Ç....Ç................ °“°√“∑√∑¥¥  ÕÕ∫∫ÀÀ““§§à“à“··√√ßߥ¥—¥—¥¢¢ÕÕß߉¡‰¡â â Õπ¡ÿ —μ‘
ººŸâπâŸπÌ“”  àßàßÇ...Ç...Ç....Ç....Ç....Ç....Ç...Ç....Ç....Ç....Ç.....Ç....Ç....Ç............
™™π𑥑¥μμ—«—«ÕÕ¬¬à“ßà“Çß..Ç....Ç.....Ç..∑Ç¥ .∑Õ¥∫ §Õ√∫ßÈ— §∑√’Ë.—Èß..∑..’ËÇ....Ç..........
∑∑¥¥  ÕÕ∫∫««—ππ— ∑∑’ËÇ.’Ë .Ç....Ç....Ç....Ç.......Ç....Ç.....··ººàππà ∑∑Ç’Ë ’Ë.......Ç............

™π‘¥‰¡âμ—«Õ¬à“ß

√“¬≈–‡Õ’¬¥ ‰¡Çâ ÇÇÇÇ ‰¡âÇÇÇÇÇÇ ‰¡Çâ ÇÇÇÇÇ

12 3 1 2 3 1 2 3

1.¡μ‘ ¢‘ Õ߉¡μâ «— Õ¬“à ß §«“¡°«“â ß b (´¡.)
§«“¡≈°÷ d (´¡.)

2.§«“¡¬“«æ°‘ ¥— L (´¡.)

3.π.π.¢Õ߉¡μâ «— Õ¬“à ß W (°√¡— )

4.§“à Àπ«à ¬·√ߧ«“¡‡§πâ ∑¢Ë’ ¥’ ªØ¿‘ “§(°°./´¡.2)
S = (3/2) {(PL) / (bd2)} („™§â “à P ∑¢Ë’ ¥’ ªØ¿‘ “§)

5.‚¡¥≈Ÿ  — ·μ°√“â « (°°./´¡.2)

RS = (3/2) {(Pmax L) / (bd2)}

6.‚¡¥≈Ÿ  — ¬¥◊ À¬πàÿ (°°./´¡.2)

E = (PL3) / (48 ΔI) („™§â “à P ∑¢Ë’ ¥’ ªØ¿‘ “§)

7.‚¡¥≈Ÿ  — §π◊ μ«— (°°./´¡.2)

MR ==SS22/ /1818EE ((„™â S ®“°¢Õâ 4 , E ®“°¢Õâ 6)
R

8.§“à Àπ«à ¬·√ߧ«“¡‡§πâ  ßŸ  ¥ÿ ¢Õß·√߇©Õ◊ π

Smax = (3/4) (Pmax/ bd) (°°./´¡.2)

9.§“à ß“π‡©≈¬Ë’ ∑πË’ “ÌÈ Àπ°— ª√–≈¬— (°°. - ´¡.)

W = Pmax Δ
max

À¡“¬‡Àμ:ÿ

1-82 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√√Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç............ ∫ø∫ø.¡.¡∑∂∂..((∑∑))220044.3.3-2-525050 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
  ∂∂““ππ∑∑’Ë°°Ë’ àÕÕà   √√â““â ßßÇ...Ç....Ç....Ç....Ç....Ç......Ç....Ç....Ç....Ç...........
Ç...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç........Ç....Ç....Ç........... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâ∑¥ Õ∫
ººŸâ√Ÿâ√—∫—∫®®â““â ßßÇ...Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç....Ç........Ç....Ç................ ºâŸμ√«® Õ∫
ºŸâπ” àß............................................................. °“√∑¥ Õ∫À“§à“·√ߥ—¥¢Õ߉¡â
ºŸâπÌ“ àßÇÇÇÇÇÇÇÇÇ..ÇÇÇÇ Õπ¡ÿ μ— ‘
™π¥‘ μ«— Õ¬“à ß............∑¥ Õ∫§√È—ß∑Ë’................... °“√∑¥ Õ∫À“§à“·√ߥ¥— ¢Õ߉¡â
™π‘¥μ—«Õ¬à“ß.ÇÇÇ.Ç..∑¥ Õ∫§√—Èß∑’ËÇ..
∑¥ Õ∫«π— ∑Ë.’ ..........................·ºàπ∑’Ë................. ™π‘¥‰¡âμ—«Õ¬à“ß
∑¥ Õ∫«—π∑’ËÇÇÇÇÇÇ.Ç.·ºàπ∑Ç’Ë Ç.

√“¬≈–‡Õ’¬¥

‰¡Çâ .ÇÇÇ ‰¡âÇÇÇÇ ‰¡âÇÇÇÇ

1.§“à ‡©≈¬Ë’ ¢ÕßÀπ«à ¬·√ߧ«“¡‡§πâ ∑¢Ë’ ¥’ ªØ¿‘ “§ S (°°./´¡.22)

2.§“à ‡©≈¬Ë’ ¢Õß‚¡¥≈Ÿ  — ·μ°√“â « Rd ((°°°°..//´¡.2)

3.§“à ‡©≈¬Ë’ ¢Õß‚¡¥≈Ÿ  — ¬¥◊ À¬πàÿ E (°(°°./.´/´¡¡.2.)2)

4.§“à ‡©≈¬Ë’ ¢Õß‚¡¥≈Ÿ  — §π◊ μ«— RM (°(°.°/´./´¡¡.2.)2)
R

5.§“à ‡©≈¬Ë’ ¢ÕßÀπ«à ¬·√ߧ«“¡‡§πâ  ßŸ  ¥ÿ ¢Õß·√߇©Õ◊ π Smax(°°./´(°¡°.2.)/´¡.2)

6. §“à ‡©≈¬Ë’ ¢Õßß“π‡©≈¬Ë’ ∑πË’ “ÌÈ Àπ°— ª√–≈¬— WAV (°°(.°°-.´-¡´.)¡.)
À¡“¬‡Àμ:ÿ

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡ 1-83

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚‚§§√√ßß°°““√√.Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç........Ç....Ç............. ∫ø∫ø.¡.¡∑∂∂..((∑∑))22040.4.-42-5255050 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇ
º∑Ÿâ ¥ Õ∫
............................................................................... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºŸâμ√«® Õ∫
 ∂“π∑’Ë°àÕ √â“ßÇÇÇÇÇÇÇÇÇÇÇ. Õπ¡ÿ μ— ‘
 ∂“π∑’Ë°àÕ √â“ß...................................................... °“√°∑“√¥∑ ¥Õ Õ∫∫ÀÀ““§§“à“à ··√√ßߥ¥¥— ¢—¥Õ¢ßÕ‰¡ßâ ‰¡â
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
...............................................................................
º√⟠∫— ®“â ßÇÇÇÇÇÇÇÇÇÇÇÇÇÇ..
º√Ÿâ —∫®“â ß..................................................................
ºπ⟠“Ì  ßà ..ÇÇÇÇÇÇÇÇÇÇÇ..ÇÇ..Ç™π¥‘ μ«— Õ
ºŸπâ ” ßà ....................................................................
¬“à ßÇÇÇÇ.Ç.∑¥ Õ∫§√ßÈ— ∑ÇË’ Ç..

∑™¥π ¥‘ Õμ∫—««Õπ— ¬∑“àÇË’ ß.Ç...Ç....Ç...Ç.∑Ç¥ ..ÕÇ∫.·§º√πà—Èß∑∑ÇË’.Ë’ ...Ç.....Ç.................

∑¥ Õ∫«π— ∑’.Ë ..........................·ºπà ∑’Ë.......................

≈—°…≥–°“√«∫‘ μ— ‘

™π‘¥¢Õ߉¡âμ—«Õ¬à“ß 123

À¡“¬‡Àμÿ

1-84 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«‘»«°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 205-2550

¡“μ√∞“π°“√∑¥ Õ∫À“§à“°”≈ß— ¥ß÷ ·≈–·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â

(Tensile and Cleavage Test of Wood)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫π’ȧ√Õ∫§≈ÿ¡∂÷ß°“√À“§ÿ≥ ¡∫—μ‘∑“ß°≈¢Õ߉¡â ‡¡◊ËÕ¡’·√ߥ÷ß„π·π«

μÈ—ß©“°°∫— ‡ ¬È’ π ·≈–·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â

2. 𑬓¡
2.1 °”≈—ߥß÷ ¢Õ߉¡â (Tensile Strength of Wood) À¡“¬∂ß÷ §«“¡ “¡“√∂¢Õ߉¡â∑∑’Ë πμàÕ·√ߥ÷ß
 ßŸ  ÿ¥μàÕ·π« μ—Èß©“°°—∫‡ ¬È’ π
2.2 ·√ßμâ“π∑“π¢Õ߉¡â (Cleavage of Wood) À¡“¬∂ß÷ ·√ß∑°Ë’ √–∑”μàÕ°“√μ“â π∑“π°“√·μ°¢Õß
‰¡â ‚¥¬·π«·μ° ®–Õ¬Ÿà„π√–π“∫¢π“π°—∫‡ ’Ȭπ ∑“ߥâ“πμ—Èß©“°°—∫«ßªï (Radial) À√◊Õ∑“ß
¥“â π —¡º— °∫— «ßªï (Tangential)

3. ™Èπ— §ÿ≥¿“æ·≈– ≠— ≈—°…≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π

°Õà  √â“ß∑—«Ë ‰ª

4. «∏‘ ∑’ ”
4.1 ‡§√Ë◊Õß¡Õ◊ ·≈–Õÿª°√≥å ª√–°Õ∫¥â«¬
‡§√Ë◊Õß¡◊Õ ”À√—∫∑¥ Õ∫·√ߥ÷ß ·≈–·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â (Special Devices
for Tensile and Cleavage Test) μ“¡√ªŸ ∑Ë’ 1

‰¡μâ «— Õ¬“à ß

‰¡μâ —«Õ¬“à ß

√Ÿª∑’Ë 1 ‡§√ÕË◊ ß¡◊Õ ”À√—∫∑¥ Õ∫°”≈ß— ¥ß÷ ·≈–·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â

À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡ 1-85

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

4.2 °“√‡μ√’¬¡μ«— Õ¬à“ß
‡μ√’¬¡‰¡âμ—«Õ¬à“ß∑Ë’‰ ‡√’¬∫ (Dressed Timber) ·≈–‡°≈’È¬ß (Clear Wood) ¢π“¥ 5x5x6

´¡. ‚¥¬¡’¢π“¥∫√‘‡«≥¢Õß à«π∑’Ë®–∑¥ Õ∫ 2.5x5 ´¡. ™π‘¥≈– 3 ∑àÕπ  ”À√—∫°“√∑¥ Õ∫·√ß
¥÷ß ·≈–¢π“¥ 5x5x9.5 ´¡. ‚¥¬¡’¢π“¥∫√‘‡«≥¢Õß à«π∑Ë’®–∑¥ Õ∫ 5x7.5 ´¡.  ”À√—∫°“√
∑¥ Õ∫·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â ‰¡âμ—«Õ¬à“ß∑Ë’®–π”¡“∑¥ Õ∫μâÕß¡’§à“§«“¡™È◊π (Moisture
Content) Õ¬√àŸ –À«“à ß√Õâ ¬≈– 10 ∂ß÷ √âÕ¬≈– 14
4.3 ·∫∫øÕ√¡å

„™â·∫∫øÕ√å¡∑Ë’ ∫ø. ¡∂.(∑) 205.1-2550 : °“√∑¥ Õ∫À“§à“°”≈—ߥ÷ß·≈–·√ßμâ“π∑“π°“√
·μ°¢Õ߉¡â ·≈– 205.2-2550 : °“√∑¥ Õ∫À“§“à °”≈ß— ¥÷ß·≈–·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â
4.4 °“√∑¥ Õ∫
4.4.1 «—¥§«“¡°«â“ߢÕ߉¡μâ —«Õ¬“à ß∑®Ë’ –„™â∑¥ Õ∫·√ߥ÷ß ·≈–·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â ‚¥¬„Àâ

Õ“à π§“à ‰¥â¡§’ «“¡≈–‡Õ¬’ ¥∂ß÷ 0.1 ´¡. ·≈–™ß—Ë π”È Àπ°— „ÀâÕ“à π§à“‰¥â ¡§’ «“¡≈–‡Õ’¬¥∂÷ß 0.1 °√—¡
4.4.2 «“߉¡μâ —«Õ¬à“ß„À‡â ¢â“∑’„Ë πμ”·Àπßà ∑Ë’· ¥ß‰«â „π√ªŸ ∑Ë’ 1 „™·â √ߥß÷ Õ¬“à ßμÕà ‡πÕ◊Ë ß¥â«¬§«“¡‡√Á«

ª√–¡“≥ 2.5 ¡¡. μÕà π“∑’ ®π∂÷ß®ÿ¥∑‰Ë’ ¡μâ —«Õ¬à“߇√Ë¡‘ ·μ° ∫π— ∑÷°§à“·√ߥß÷  Ÿß ÿ¥∑ÕË’ à“π§à“‰¥â
4.4.3 §“à °”≈ß— ¥ß÷ ¢Õ߉¡â À“‰¥‚â ¥¬π”§“à ¢Õß·√ߥ÷ߠߟ  ¥ÿ ∑Õ’Ë “à π‰¥â À“√¥â«¬æ◊πÈ ∑Ë∫’ √‡‘ «≥ à«π∑’Ë

·§∫∑’Ë ¥ÿ
4.4.4 æ‘®“√≥“À“§“à ¢Õß·√ßμ“â π∑“π°“√·μ°¢Õ߉¡μâ àÕ‡´π쇑 ¡μ√ ¢Õߧ«“¡°«â“ߢÕ߉¡â

μ«— Õ¬“à ß

5. °“√§”π«≥
„À⥔‡ππ‘ °“√§”π«≥μ“¡«‘∏’∑Ë°’ ”À𥉫„â π·∫∫øÕ√¡å μ“¡¢âÕ 4.3

6. °“√√“¬ß“π
„Àâ√“¬ß“πμ“¡·∫∫øÕ√¡å „π¢Õâ 4.3

7. ‡°≥±°å “√μ—¥ π‘ ·≈–§«“¡§≈“¥‡§≈Ë◊Õπ∑¬Ë’ Õ¡„Àâ
‡°≥±å°“√μ—¥ ‘π„À⇪ìπ‰ªμ“¡ ¡∂. 104 : ¡“μ√∞“πß“π‰¡â ‚¥¬„™â§à“‡©≈Ë’¬°“√∑¥ Õ∫·√ß

¥÷ß ·≈–·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â ·μà≈–™π¥‘ μ“¡·∫∫øÕ√¡å „π¢Õâ 4.3

8. ¢âÕ§«√√–«—ß
8.1 ‰¡μâ —«Õ¬“à ß∑’®Ë –π”¡“∑¥ Õ∫μâÕßÕ¬„Ÿà π ¿“æ∑ ’Ë ¡∫Ÿ√≥å‡√’¬∫√âÕ¬ ¡¢’ π“¥μ“¡∑’°Ë ”Àπ¥‡∑“à °π—
μ≈Õ¥∑—Èß∑Õà π ·≈–μâÕ߉¡à¡’μ”Àπ„‘ π‡πÈÕ◊ ‰¡â
8.2 „π°“√∑¥ Õ∫„À⫓߉¡μâ «— Õ¬à“ß„πμ”·Àπßà ∑Ë∂’ °Ÿ μâÕß·≈–¡Ëπ— §ß

9. Àπ—ß ◊ÕÕ“â ßÕß‘
9.1 ¡“μ√∞“π«»‘ «°√√¡ ∂“π·Ààߪ√–‡∑»‰∑¬ ¡“μ√∞“π ”À√—∫Õ“§“√‰¡â æ‘¡æå§√Èß— ∑’Ë 5 æ.». 2526
9.2 ¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424-2530 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π°àÕ √“â ß∑Ë«— ‰ª
9.3 FACULTY OF ENGINEERING CHULALONGKORN UNIVERSITY MATERIAL TESTING
LABORATORY TEST NO.T 5 TENSILE AND CLEAVAGE TEST OF WOOD
9.4 ASTM DESIGNATION : D 143-83 STANDARD METHODS OF TESTING SMALL CLEAR
SPECIMENS OF TIMBER.

1-86 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ«’ »‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇ.... ∫∫øø.¡. ∑¡∂.(∑) 220055..11--22555500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇ
‚§√ß°“√.......................................................... ºŸ∑â ¥ Õ∫
 ∂“π∑’Ë°àÕ √â“ßÇÇÇÇÇÇÇÇÇÇÇ (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºâŸμ√«® Õ∫
 ∂“π∑Ë’°Õà  √â“ß............................................... °“√∑¥ Õ∫À“§à“ Õπÿ¡μ— ‘
Ç..Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç...
ººŸâ√—∫Ÿ√â —∫®®â““âßßÇ...Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....... °Ì“≈—ߥ÷ß·≈–·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â

ººŸâπâπŸÌ“”  àßàßÇ...Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....

™™ππ‘¥¥‘μμ—««— ÕÕ¬¬à““à ßß..Ç....Ç....Ç...∑ǥǠÕ∑∫¥§ √Èß—Õ∑∫.Ë’ §...√..—Èß..∑...’ËÇ........

∑∑¥¥  ÕÕ∫∫««—ππ— ∑∑’ËÇ’.Ë ...Ç....Ç....Ç....Ç....Ç....Ç...·Çºπà.·∑º.Ë’ .àπ...∑...’ËÇ..........

°“√°∑“¥√∑ ¥Õ ∫ÕÀ∫“°§Ì“à“≈°—ß”¥≈÷ßß—¢¥Õß÷ ‰¢¡Õâ ß(T‰¡ENâ (STIeOnNsioTEnSTTe)st)

™π‘¥‰¡âμ—«Õ¬à“ß

√“¬≈–‡Õ’¬¥ ‰¡âÇÇÇÇÇÇÇÇÇÇ ‰¡âÇÇÇÇÇÇÇÇÇÇ ‰¡Çâ ÇÇÇÇÇÇÇ

1 2 3 1 2 3 1 23

1.¡μ‘ ¢‘ Õ߉¡μâ «— Õ¬“à ß §«“¡¬“« a (´¡.)
§«“¡°«“â ß b (´¡.)

2.§«“¡≈°÷ ¢Õ߉¡μâ «— Õ¬“à ß d (´¡.)

3.π.π.¢Õ߉¡μâ «— Õ¬“à ß w (°.)

4.§«“¡™πÈ◊ ¢Õ߉¡μâ «— Õ¬“à ß (√âÕ¬≈–)

5.æπÈ◊ ∑ÀË’ π“â μ¥— ∑„Ë’ ™∑â ¥ Õ∫ , A = a x b (´¡.2)

6.§“à ·√ߥß÷  ßŸ  ¥ÿ , P (°°.)
7.§“à °“Ì ≈ß— ¥ß÷ ¢Õ߉¡â , δ = P / A (°°./´¡.2)

8. §“à ‡©≈¬Ë’ °“Ì ≈ß— ¥ß÷ ¢Õ߉¡â , δAV (°°./´¡.2)

d

a
b

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ«’ »‘ «°√√¡ 1-87

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

‚§√ß°“√ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ∫∫øø.¡. ∑¡∂.(∑) 220055..22--22555500 ∑–‡∫’¬π∑¥ Õ∫ÇÇÇÇÇÇ
 ‚∂§“√πß∑°’Ë°“√àÕ. ...√..â“..ß..Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç...... ºâŸ∑¥ Õ∫
 ∂“π∑°’Ë àÕ √â“ß............................................... (Àπ૬ߓπ∑’Ë∑Ì“°“√∑¥ Õ∫) ºâŸμ√«® Õ∫
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ °“√∑¥ Õ∫À“§à“ Õπÿ¡μ— ‘
........................................................................
ººŸâ√—∫Ÿâ√∫— ®®â“â“ßßÇ...Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....... °Ì“≈—ߥ÷ß·≈–·√ßμâ“π∑“π°“√·μ°¢Õ߉¡â
ººŸâππŸâ Ì“”  àßàßÇ...Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....Ç.....Ç....Ç....Ç....Ç....Ç....

™™ππ‘¥¥‘μμ—«—«ÕÕ¬¬à“à“ßßÇ....Ç....Ç....Ç∑¥Ç Õ∑∫¥§ √Õß—È ∫∑§’Ë...√..—Èß..∑...’ËÇ.........

∑∑¥¥  ÕÕ∫∫««—π—π∑∑’ËÇ’Ë....Ç....Ç....Ç....Ç....Ç....Ç...·Çºπà.·∑ºË.’ .àπ...∑...’ËÇ.........

°“√∑¥  ÕÕ∫∫··√√ßßμμâ“â“ππ∑∑“π“π°“°√“·√μ·°μ¢°Õ¢ßÕ‰¡ßâ‰(¡Câ (LCEleAaVvAaGgEe TTEeSsTt)

√“¬≈–‡Õ’¬¥ ™π‘¥‰¡âμ«— Õ¬à“ß ‰¡Çâ ÇÇÇÇÇÇÇ.

‰¡Çâ ÇÇÇÇÇÇÇÇÇ ‰¡Çâ ÇÇÇÇÇÇÇÇ 123

123123

1.¡μ‘ ¢‘ Õ߉¡μâ «— Õ¬“à ß §«“¡¬“« a (´¡.)
§«“¡°«“â ß b (´¡.)

2.§«“¡≈°÷ ¢Õ߉¡μâ «— Õ¬“à ß d (´¡.)

3. π.π.¢Õ߉¡μâ «— Õ¬“à ß w (°.)
4. §«“¡™πÈ◊ ¢Õ߉¡μâ «— Õ¬“à ß (√Õâ ¬≈–)
5. §“à ·√ߥß÷  ßŸ  ¥ÿ , P (°°.)

6.§“à ·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â = P / b (°°./´¡.)

7.§“à ‡©≈¬Ë’ ·√ßμ“â π∑“π°“√·μ°¢Õ߉¡â (°°./´¡.)

d a
b

1-88 À¡«¥ß“π‚§√ß √“â ß·≈–ª∞æ’«»‘ «°√√¡

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

¡∂.(∑) 206-2550
¡“μ√∞“π°“√∑¥ Õ∫À“§“à ·√߇©◊Õπ¢π“π‡ ¬È’ π¢Õ߉¡â

(Shear Test of Wood Parallel to Grain)

1. ¢Õ∫¢“à ¬
¡“μ√∞“π°“√∑¥ Õ∫πÈ’§√Õ∫§≈ÿ¡∂÷ß°“√À“§à“§«“¡ “¡“√∂„π°“√√—∫·√߇©◊Õπ¢Õ߉¡â„π

·π«¢π“π‡ ’È¬π

2. 𬑠“¡
§«“¡ “¡“√∂„π°“√√—∫·√߇©◊Õπ¢Õ߉¡â À¡“¬∂÷ß §«“¡ “¡“√∂¢Õ߉¡â„π°“√μâ“π∑“π

·√߇§âπ ∑Ë’®–∑”„Àâ à«π¢ÕßÀπâ“μ¥— ‰¡∑â ËÕ’ ¬„àŸ π√–π“∫‡¥¬’ «°—∫·π«·√߇≈Ë◊ÕπÕÕ°®“°°—π

3. ™—πÈ §≥ÿ ¿“æ·≈– ≠— ≈—°…≥å
„À⇪ìπ‰ªμ“¡¡“μ√∞“πº≈‘μ¿—≥±åÕÿμ “À°√√¡ ¡Õ°. 424 ‰¡â·ª√√Ÿª :  ”À√—∫ß“π°àÕ √â“ß

∑—«Ë ‰ª

4. «‘∏’∑”
4.1 ‡§√ÕË◊ ß¡Õ◊ ·≈–Õÿª°√≥å ª√–°Õ∫¥«â ¬
4.1.1 ‡§√Õ◊Ë ß¡◊Õ∑¥ Õ∫·√߇©◊Õπ ∑Ë¡’ ≈’ °— …≥–‡™πà ‡¥’¬«°∫— ∑’·Ë  ¥ß„π√Ÿª∑Ë’ 1 ‚¥¬„À¡â ’√–¬–
À“à ß√–À«“à ߢÕ∫¥“â π„π¢Õߺ«‘ ∑√Ë’ Õß√∫— °∫— √–π“∫∑®’Ë –‡°‘¥°“√«∫‘ —μ‘¢Õ߉¡â ‡∑“à °∫— 3 ¡.¡.

π”È Àπ°— °¥
·ºàπ‡À≈°Á °¥

‰¡âμ«— Õ¬à“ß

√ªŸ ∑’Ë 1 ‡§√Ë◊Õß¡◊Õ∑¥ Õ∫À“§“à ·√߇©Õ◊ π¢π“π‡ ’¬È π¢Õ߉¡â

À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡ 1-89

°√¡∑“ßÀ≈«ß™π∫∑ °√–∑√«ß§¡π“§¡

4.2 °“√‡μ√¬’ ¡μ—«Õ¬à“ß
4.2.1 ‡μ√¬’ ¡‰¡μâ «— Õ¬à“ß∑’ˉ ‡√’¬∫ (Dressed Timber) ·≈–‡°≈¬È’ ß (Clear Wood) ¢π“¥
5x5x6.3 ´¡. ‚¥¬„Àâ¡’æ◊Èπ∑’Ë∑’Ë®–√—∫·√߇©◊Õπ‡¡Ë◊Õ∑”°“√∑¥ Õ∫ ‡∑à“°—∫ 5 x 5 ´¡. ¥—ß
· ¥ß„π√ªŸ ∑Ë’ 2
4.2.2 ‰¡âμ«— Õ¬“à ß∑’®Ë –π”¡“∑¥ Õ∫ μÕâ ß¡§’ «“¡™È◊π (Moisture Content) Õ¬Ÿ√à –À«à“ß√Õâ ¬≈–
10 ∂ß÷ √Õâ ¬≈– 14

AA C A = 5 ´¡., B = 5 ´¡.
EEE C = 5 ´¡., D = 6.3 ´¡.
BB C E = 2 ´¡.

C

DD

√ªŸ ∑Ë’ 2 ‰¡âμ«— Õ¬“à ß

4.3 ·∫∫øÕ√å¡
„™·â ∫∫øÕ√å¡∑’Ë ∫ø. ¡∂.(∑) 206.1-2550 : °“√∑¥ Õ∫À“§“à ·√߇©◊Õπ¢π“π‡ È’¬π¢Õ߉¡â

4.4 °“√∑¥ Õ∫
4.4.1 ™Ë—ßπ”È Àπ—° ‰¡μâ —«Õ¬à“ß „À≈â –‡Õ¬’ ¥ ∂ß÷ 0.1 °√—¡
4.4.2 «—¥¢π“¥ ‰¡μâ —«Õ¬à“ß „Àâ≈–‡Õ’¬¥ ∂÷ß 0.1 ¡.¡.
4.4.3 ∫π— ∑÷°≈°— …≥–∑»‘ ∑“ß ¢Õß≈“¬‰¡â («ßªï) ¢Õßæπ◊È ∑’∑Ë ’Ë√—∫·√߇©Õ◊ π«à“Õ¬Ÿ„à π≈°— …≥–μ—ßÈ
©“°°—∫«ßªï (Radial) À√◊Õ —¡º— °—∫«ßªï (Tangential) À√◊ÕÕ¬àŸ√–À«à“ß·π«μÈ—ß©“°·≈–
·π« ¡— º— °—∫«ßªï (Intermediate)
4.4.4 «“߉¡âμ—«Õ¬“à ß≈ß„π‡§√Õ◊Ë ß¡Õ◊ ∑¥ Õ∫„π≈°— …≥–¥ß— μàÕ‰ªπÈ’
4.4.4.1 ‰¡¡à ’°“√∫¥‘ μ«— ¢Õ߉¡âμ—«Õ¬à“ß ‡¡ÕË◊ ¡’·√ß°√–∑”
4.4.4.2 «“߉¡μâ «— Õ¬“à ß„ÀÕâ ¬à„Ÿ π·π«¥‘ßË
4.4.4.3 æ◊πÈ º‘«≈à“ߢÕ߉¡μâ —«Õ¬à“ß«“ß„À‰â ¥√â –π“∫∫π∑Ë’√Õß√—∫
4.4.5 §àÕ¬Ê ª√—∫‡§√◊ËÕß¡Õ◊ „À‡â ¢“â ∑Ë’·≈â«∑”°“√∑¥ Õ∫ ‚¥¬„À·â ºπà ‡À≈°Á °¥‡§≈◊ËÕπ∑Ë’¥«â ¬
§«“¡‡√Á«‰¡à¡“°°«à“ 2 ¡.¡. μÕà π“∑’ ®π‰¡μâ —«Õ¬“à ߇°¥‘ °“√«∫‘ μ— ‘
4.4.6 ∫—π∑°÷ §à“·√ß°√–∑” Ÿß ÿ¥ ·≈–≈—°…≥–°“√«∫‘ —μ¢‘ Õ߉¡μâ «— Õ¬“à ß

1-90 À¡«¥ß“π‚§√ß √â“ß·≈–ª∞æ’«»‘ «°√√¡